Jump to ContentJump to Main Navigation
Show Summary Details
More options …

Journal of Basic and Clinical Physiology and Pharmacology

Editor-in-Chief: Horowitz, Michal

Editorial Board: Das, Kusal K. / Epstein, Yoram / S. Gershon MD, Elliot / Haim, Abraham / Kodesh , Einat / Kohen, Ron / Lichtstein, David / Maloyan, Alina / Mechoulam, Raphael / Roth, Joachim / Schneider, Suzanne / Shohami, Esther / Sohmer, Haim / Yoshikawa, Toshikazu

6 Issues per year


CiteScore 2016: 1.01

SCImago Journal Rank (SJR) 2016: 0.349
Source Normalized Impact per Paper (SNIP) 2016: 0.495

Online
ISSN
2191-0286
See all formats and pricing
More options …
Volume 28, Issue 6

Issues

Central mediators of the zymosan-induced febrile response

Amanda Leite Bastos-Pereira
  • Department of Pharmacology, Biological Sciences Sector, Federal University of Paraná, Curitiba, Brazil
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Daniel Fraga
  • Department of Pharmacology, Biological Sciences Sector, Federal University of Paraná, Curitiba, Brazil
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Arturo Alejandro Dreifuss
  • Department of Pharmacology, Biological Sciences Sector, Federal University of Paraná, Curitiba, Brazil
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Aleksander Roberto Zampronio
  • Corresponding author
  • Department of Pharmacology, Centro Politécnico, Setor de Ciências Biológicas, Universidade Federal do Paraná, Caixa Postal 19031, Curitiba, Paraná, 81530-980, Brazil, Phone: +55 41 3361-1540, Fax: +55 41 3266-2042
  • Email
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
Published Online: 2017-10-05 | DOI: https://doi.org/10.1515/jbcpp-2017-0061

Abstract

Background:

Zymosan is a fungal cell wall protein-carbohydrate complex that is known to activate inflammatory pathways through the Toll-like receptors and is commonly used to induce fever. Nevertheless, the central mediators that are involved in the zymosan-induced febrile response are only partially known.

Methods:

The present study evaluated the participation of prostaglandins, substance P, endothelin-1 (ET-1), and endogenous opioids (eOPs) in the zymosan-induced febrile response by using inhibitors and antagonists in male Wistar rats.

Results:

Both nonselective (indomethacin) and selective (celecoxib) cyclooxygenase inhibitors reduced the febrile response induced by an intraperitoneal (i.p.) injection of zymosan. Indomethacin also blocked the increase in the prostaglandin E2 levels in the cerebrospinal fluid. An intracerebroventricular injection of the neurokinin-1, ETB, and μ-opioid receptor antagonists also reduced the febrile response induced by the i.p. injected zymosan. Moreover, the μ-opioid receptor antagonist CTAP also reduced the febrile response induced by intra-articular injection of zymosan.

Conclusions:

These results demonstrate that prostaglandins, substance P, ET-1, and eOPs are central mediators of the zymosan-induced febrile response.

Keywords: endothelin; fever; opioid; prostaglandin; substance P; zymosan

Introduction

Prostaglandins are the most widely known central mediators of the febrile response. Prostaglandin E2 (PGE2) is synthesized through the metabolism of arachidonic acid by cyclooxygenase-2 (COX-2) and microsomal PGE synthase-1 (mPGES1) [1], [2], [3]. The production of this eicosanoid occurs mainly in the brain, specifically in the endothelial cells [4], although some evidence indicate that the peripheral synthesis of prostaglandins also contributes to the initial phase of fever [5]. Once released, these prostanoids can easily reach the medial preoptic nucleus of the hypothalamus to produce fever by acting on prostaglandin EP3 receptors [6], [7], [8]. Most of the studies above, which reported the involvement of prostaglandins in fever, used lipopolysaccharide (LPS) to induce fever to simulate Gram-negative bacterial infections [1], [2], [4], [5], [6], [7].

However, LPS-induced fever also relies on other central mediators beyond prostaglandins. The first of the mediators identified was the corticotropin-releasing factor (CRF). In 1989, Rothwell showed that the CRF receptor antagonist α-helical CRF9-41 attenuated the increases in body temperature, oxygen consumption, and brown adipose tissue activity, which were observed after the central administration of interleukin-1β (IL-1β), one of the main pyrogenic cytokines [9]. Subsequent studies have shown that the CRF receptor antagonists reduced the febrile response induced by several pyrogenic mediators [10], [11]. The blockade of the actions of substance P in the brain using the neurokinin-1 (NK1) receptor antagonists reduced LPS-induced fever [12], [13], [14], suggesting that substance P is also a central mediator of LPS-induced fever. However, substance P does not participate in the febrile response induced by some endogenous pyrogens, such as IL-1β and the chemokine CCL3 [14]; however, it is involved in the febrile response induced by tumor necrosis factor-α (TNF-α), IL-6, and PGE2 [15].

In 1998, Fabrício et al. [16] showed that endothelin-1 (ET-1) induced fever when it was injected directly in the brain, and that the ETB receptor antagonist BQ788 reduced LPS-induced fever. These results and those of the following studies [17], [18] confirmed that ET-1 is a central mediator of fever. The first study that suggested that endogenous opioids (eOPs) also participated in the LPS-induced febrile response was published by Blatteis et al. [19]. Fraga et al. [20] further confirmed these results by proving that μ-opioid receptors (MORs) are involved in modulating fever. Some redundancy in the pathways that lead to the release of these central mediators (i.e. eOPs and ET-1) induces fever independently of the prostaglandin synthesis, whereas substance P appears to act in concert with prostaglandins in the autocrine circuitry [15], [21]. The CRF appears to be involved in both prostaglandin-dependent and -independent mechanisms (for review, see [21]).

Zymosan is an insoluble protein-carbohydrate complex from the yeast cell and has been used to induce fever, thus mimicking the febrile response that is induced by fungi [22]. Past studies that used this pyrogen have intraperitoneally (i.p.) or intra-articularly (i.a.) injected zymosan, but the mediators that are involved in this febrile response are scarcely known. Kanashiro et al. [23] showed that an i.a. injection of zymosan produced a febrile response in rats that depended on the prostaglandin synthesis. In contrast to the LPS, the zymosan-induced febrile response did not depend on CRF or ET-1 synthesis [24].

We and others recently showed that cytokines, such as IL-1β, IL-6, and TNF-α, which are produced peripherally or in the central nervous system are involved in the febrile response induced by both i.p. and i.a. zymosan administration [24], [25]. However, it remains unknown whether substance P and eOPs participate in the febrile response induced by zymosan.

The aim of the present study was to evaluate the central mediators, specifically substance P and eOPs, which are involved in the febrile response induced by the i.p. injected zymosan. We also evaluated whether, similar to what was observed with the i.a. injection of zymosan, the febrile response induced by the i.p. injected zymosan is mediated by prostaglandins but not by ET-1.

Materials and methods

Animals

The experiments were conducted with 132 male Wistar rats (180–220 g), which were housed 4 per cage at 22°C±1°C under a 12 h/12 h light–dark cycle (lights on at 7:00 a.m.) with free access to food chow and tap water. All of the experiments were approved by the institution’s Ethical Committee on Animal Use, in accordance with the Brazilian and International Guidelines for Animal Care.

Abdominal temperature measurement

Abdominal body temperature (Tb) was measured in conscious unrestrained rats using data loggers (Subcue, Calgary, Canada). Briefly, data loggers were implanted in the peritoneal cavity under ketamine (90 mg/kg) and xylazine (7.5 mg/kg) anesthesia under aseptic conditions at least 5 days prior to the experiment. The animals were treated with oxytetracycline hydrochloride (400 mg/kg, intramuscular) and ketoprofen (10 mg/kg, orally) immediately after surgery. On the day of the experiment, body temperature was continuously monitored at 15-min intervals beginning 2 h before any injection until 6 h after the injection of the pyrogenic stimulus. During the experiment, the room temperature was maintained at 28°C±1°C (i.e. the thermoneutral zone for rats) [26].

Intracerebral cannula implantation and microinjection

For the intracerebroventricular (i.c.v.) administration of BQ788, SR140333B, and CTAP, a 22-gauge stainless-steel guide cannula (0.8 mm outer diameter, 12 mm length) was sterotaxically implanted above the right lateral ventricle under the same anesthesia that was used for data logger implantation according to the following coordinates: 0.8 mm lateral to the midline, 1.5 mm posterior to the bregma, and 2.5 mm below the brain surface, with the incisor bar lowered 3.3 mm below the horizontal zero [27]. The cannulas were fixed to the skull with jeweler’s screws and embedded in dental acrylic cement. Microinjections were made aseptically using a 30-gauge needle that was connected to a polyethylene-10 tubing. The needle protruded 2 mm beyond the cannula tip to reach the right lateral ventricle, and a 2 μL volume was slowly injected over 1 min using a 25 μL Hamilton syringe. After the injection, the needle was left in place for 30 s before it was withdrawn to prevent the backflow of the injection fluid through the cannula. After the experiment, each rat received a microinjection of Evans blue (2.5% in saline) in the lateral ventricle. Finally, the brains were removed, and animals that had cannula misplacements, cannula blockage, or abnormal body weight gain after surgery were excluded from the study.

Experimental protocols

All the pyrogenic stimuli were injected between 9:00 a.m. and 11:00 a.m. to avoid the circadian differences in body temperature. In the first set of experiments, we evaluated the participation of prostaglandins in the febrile response induced by the i.p. injected zymosan. The animals received zymosan (3 mg/kg, i.p.) that was suspended in sterile saline or the same volume of vehicle and after 2.5 h, they received the nonselective COX inhibitor indomethacin (2 mg/kg, i.p.) or the same volume of vehicle (Tris-HCl buffer, 0.2 M). In another experiment, the animals received the nonselective COX inhibitor indomethacin (2 mg/kg, i.p.), the selective COX-2 inhibitor celecoxib (5 mg/kg, v.o.), or the same volume of vehicle (Tris-HCl buffer, 0.2 M). After 30 min, the animals received zymosan (3 mg/kg, i.p.) suspended in sterile saline or the same volume of vehicle. The doses of indomethacin, celecoxib, and zymosan were based on previous works [15], [23], [25]. The core body temperature was measured for 6 h. In a different group of animals, the same protocol described above for the pre-treatment with indomethacin was used, but the experiment was interrupted 3 h after the zymosan injection to collect the cerebrospinal fluid (CSF) for PGE2 measurements (described below).

Next, we evaluated the participation of substance P, ET-1, and eOPs in the zymosan-induced febrile response. The animals intracerebroventricularly (i.c.v.) received the NK1 receptor antagonist SR140333B (3 μg/site), ETB receptor antagonist BQ788 (0.7 μg/site), or MOR antagonist CTAP (1 μg/site) in a volume of 2 μL or the same volume of sterile saline. The effective doses of antagonists were based on previous studies using LPS and polyinosinic: polycytidylic acid [28]. After 30 min, the animals received zymosan (3 mg/kg, i.p.).

Previous studies have shown that the i.a. injected zymosan induces a febrile response that is not blocked by a ETB receptor antagonist [24]. To clarify the specific pathways that involve ET-1 and eOPs, a separate group of animals received the same dose of i.c.v. CTAP. After 30 min, the animals received an i.a. injection of zymosan (4 mg/site, 50 μL) in the right knee joint as described previously [24].

Determination of PGE2 concentrations in the cerebrospinal fluid

A single sample of CSF was collected from each animal according to Consiglio and Lucion [29]. Briefly, 3 h after the zymosan or saline injection, animals that were pre-treated with vehicle or indomethacin were anesthetized with ketamine/xylazine at the same doses described above and fixed in a stereotaxic apparatus. The cisterna magna could be easily visualized by shaving the top and back of the animal and moistening this region with a cotton swab embedded in ethanol. CSF was directly aspirated from the cisterna magna through a syringe in a volume of 50–100 μL. The CSF samples were transferred to small plastic tubes that contained 2 μL of indomethacin (2.5 mg/mL) to stop further the prostaglandin synthesis and stored in the dark under ice. The samples were then centrifuged at 1000×g at 4°C for 10 min and stored at –80°C for further analysis. The PGE2 levels in the CSF were analyzed by an enzyme-linked immunosorbent assay kit (Cayman Chemical, Ann Arbor, MI, USA). All the samples were assayed according to the manufacturer’s instructions.

Drugs

Zymosan, indomethacin, celecoxib, BQ788, and CTAP were purchased from Sigma Aldrich (St. Louis, MO, USA). SR140333B was a kind donation from Sanovis-Aventis Laboratories. Ketamine hydrochloride was purchased from Vetnil Veterinary Products (Louveira, SP, Brazil). Xylazine hydrochloride was purchased from Syntec Laboratory (Cotia, SP, Brazil). Oxytetracycline hydrochloride was purchased from Pfizer Laboratories (São Paulo, SP, Brazil). Ketoprofen was purchased from Medley Laboratories (São Paulo, SP, Brazil).

Statistical analysis

The body temperature data were analyzed by two-way repeated-measures analysis of variance (ANOVA) followed by Bonferroni’s test. PGE2 levels were analyzed by one-way ANOVA followed by Bonferroni’s test. All the results were expressed as mean±SEM and were analyzed using Prism 6 software (GraphPad, San Diego, CA, USA). Values of p<0.05 were considered statistically significant.

Results

The i.p. injected zymosan induced a febrile response that began 2 h after the injection and lasted until 5 h (Figures 1 and 2). The treatment of the animals with indomethacin 2.5 h after the injection of zymosan (at the time that the animals were already febrile) significantly reduced the duration of the fever which lasted until 3.5 h. The significative differences between the zymosan plus indomethacin-treated group and the zymosan plus vehicle-treated group were observed from 255 and 355 min, respectively (Figure 1). Additionally, the pre-treatment of the animals with indomethacin completely blocked this febrile response (Figure 2A). The zymosan-induced febrile response was followed by an increase in the levels of PGE2 in CSF that was also completely blocked by the pretreatment with indomethacin (Figure 2B). Treatment with the COX-2 selective inhibitor celecoxib also completely inhibited the febrile response by zymosan (Figure 2C). Figures 3A and B show that both the NK1 receptor antagonist SR140333B and ETB receptor antagonist BQ788 significantly inhibited the febrile response induced by zymosan. Furthermore, the zymosan-induced febrile response was significantly reduced by the MOR antagonist CTAP (Figure 4A). Intra-articular zymosan administration induced a more prolonged and intense febrile response that began approximately 1.5 h after administration and lasted until the end of the experiment (Figure 4B). Treatment with CTAP significantly reduced this response.

Effects of the cyclooxygenase inhibitor indomethacin on the febrile response induced by zymosan. The rats received zymosan (Zym; 3 mg/kg, i.p.) or the same volume of vehicle (Veh, saline). After 2.5 h, they received an injection of indomethacin (Ind; 2 mg/kg, i.p.) or the same volume of vehicle (Veh; Tris-HCl buffer, 0.2 M). Body temperature was measured every 15 min for 6 h. The data are expressed as mean±SEM body temperature (°C) in 4–6 animals. The arrow represents the time of indomethacin or vehicle injection. ap<0.05, compared with the Veh/Veh group; bp<0.05, compared with the Zym/Veh group.
Figure 1:

Effects of the cyclooxygenase inhibitor indomethacin on the febrile response induced by zymosan.

The rats received zymosan (Zym; 3 mg/kg, i.p.) or the same volume of vehicle (Veh, saline). After 2.5 h, they received an injection of indomethacin (Ind; 2 mg/kg, i.p.) or the same volume of vehicle (Veh; Tris-HCl buffer, 0.2 M). Body temperature was measured every 15 min for 6 h. The data are expressed as mean±SEM body temperature (°C) in 4–6 animals. The arrow represents the time of indomethacin or vehicle injection. ap<0.05, compared with the Veh/Veh group; bp<0.05, compared with the Zym/Veh group.

Effects of the cyclooxygenase inhibitors on the febrile response and increase in prostaglandin levels induced by zymosan. The rats received an injection of indomethacin (Ind; 2 mg/kg, i.p.) (A, B) or celecoxib (Cel; 5 mg/kg, v.o.) (C) or the same volume of vehicle (Veh; Tris-HCl buffer, 0.2 M). After 30 min, they received zymosan (Zym; 3 mg/kg, i.p.) or the same volume of vehicle (saline). Body temperature was measured every 15 min for 6 h (A, C), or CSF samples were collected 3 h after the zymosan injection to determine PGE2 levels (B). The data are expressed as mean±SEM body temperature (°C) or concentration of PGE2 (pg/mL) in 5–8 animals. ap<0.05, compared with the Ind/Veh or Cel/Veh group; bp<0.05, compared with the Veh/Zym group.
Figure 2:

Effects of the cyclooxygenase inhibitors on the febrile response and increase in prostaglandin levels induced by zymosan.

The rats received an injection of indomethacin (Ind; 2 mg/kg, i.p.) (A, B) or celecoxib (Cel; 5 mg/kg, v.o.) (C) or the same volume of vehicle (Veh; Tris-HCl buffer, 0.2 M). After 30 min, they received zymosan (Zym; 3 mg/kg, i.p.) or the same volume of vehicle (saline). Body temperature was measured every 15 min for 6 h (A, C), or CSF samples were collected 3 h after the zymosan injection to determine PGE2 levels (B). The data are expressed as mean±SEM body temperature (°C) or concentration of PGE2 (pg/mL) in 5–8 animals. ap<0.05, compared with the Ind/Veh or Cel/Veh group; bp<0.05, compared with the Veh/Zym group.

Effects of the NK1 and ETB receptor antagonists on the febrile response induced by zymosan. The rats received an i.c.v. injection of the NK1 receptor antagonist SR140333B (3 μg, 2 μL) (A), the ETB receptor antagonist BQ788 (0.7 μg, 2 μL) (B), or the same volume of vehicle (Veh; saline). After 30 min, they received zymosan (Zym; 3 mg/kg, i.p.) or the same volume of vehicle (saline). Body temperature was measured every 15 min for 6 h. The data are expressed as mean±SEM body temperature (°C) in 5–7 animals. ap<0.05, compared with the SR140333B/Veh or BQ788/Veh group; bp<0.05, compared with the Veh/Zym group.
Figure 3:

Effects of the NK1 and ETB receptor antagonists on the febrile response induced by zymosan.

The rats received an i.c.v. injection of the NK1 receptor antagonist SR140333B (3 μg, 2 μL) (A), the ETB receptor antagonist BQ788 (0.7 μg, 2 μL) (B), or the same volume of vehicle (Veh; saline). After 30 min, they received zymosan (Zym; 3 mg/kg, i.p.) or the same volume of vehicle (saline). Body temperature was measured every 15 min for 6 h. The data are expressed as mean±SEM body temperature (°C) in 5–7 animals. ap<0.05, compared with the SR140333B/Veh or BQ788/Veh group; bp<0.05, compared with the Veh/Zym group.

Effect of the MOR antagonist on the febrile response induced by zymosan. The rats received an i.c.v. injection of the MOR antagonist CTAP (1 μg, 2 μL) or the same volume of vehicle (Veh; saline). After 30 min, they received an i.p. (A) or i.a. (B) injection of zymosan (Zym; 3 and 4 mg, respectively, 50 μL) or the same volume of vehicle (saline). Body temperature was measured every 15 min for 6 h. The data are expressed as mean±SEM body temperature (°C) in 5–8 animals. ap<0.05, compared with the CTAP/Veh group; bp<0.05, compared with the Veh/Zym group.
Figure 4:

Effect of the MOR antagonist on the febrile response induced by zymosan.

The rats received an i.c.v. injection of the MOR antagonist CTAP (1 μg, 2 μL) or the same volume of vehicle (Veh; saline). After 30 min, they received an i.p. (A) or i.a. (B) injection of zymosan (Zym; 3 and 4 mg, respectively, 50 μL) or the same volume of vehicle (saline). Body temperature was measured every 15 min for 6 h. The data are expressed as mean±SEM body temperature (°C) in 5–8 animals. ap<0.05, compared with the CTAP/Veh group; bp<0.05, compared with the Veh/Zym group.

Discussion

The present study showed that the central mediators involved in the i.p. zymosan-induced febrile response are similar to those of the LPS-induced febrile response. Zymosan is a protein-carbohydrate complex that is extracted from the cell wall of the yeast Saccharomyces cerevisae. Zymosan is commonly used to induce experimental inflammation, and can induce signs of local inflammation, such as neutrophil migration [30], hyperalgesia [31], and edema [32]. It also induces systemic effects, such as sickness behavior [33] and fever [23], [25]. Zymosan was originally described as a Toll-like receptor 2 agonist [34], but it also binds to the pattern-recognition receptor dectin-1, a C-like lectin receptor [35]. We previously showed that the increase in body temperature induced by the i.p. injected zymosan, similar to the i.a. injected zymosan, involves an integrated febrile response, in which the increase in the core body temperature is preceded by a decrease in tail skin temperature [25].

Bastos-Pereira found that IL-1β, IL-6, and TNF-α participate in the febrile response induced by the i.p. injected zymosan [25]. These cytokines are known to induce fever through the induction of COX-2 in the brain microvasculature [36], [37], [38]. The participation of eicosanoids in the febrile response induced by zymosan was also investigated. The zymosan administration significantly increased PGE2 levels in the CSF. Moreover, the nonselective COX inhibitor indomethacin, before or after the induction of fever, significantly reduced the febrile response and abolished the increase in PGE2 levels in the brain. A similar reduction of the febrile response was observed with the treatment using the selective COX-2 inhibitor celecoxib. These results suggest that zymosan-induced fever depends on prostaglandins that are produced via COX-2, thus corroborating previous findings reported by Kanashiro et al. [23] using an i.a. injection of zymosan.

In a recent study, we demonstrated that TNF-α, IL-6, and prostaglandins in autocrine circuitry, together with substance P, participate in fever induction [15]. The generation of PGE2 in the central nervous system during fever can initiate the release of substance P, which in turn generates more prostaglandins. Therefore, we evaluated the participation of substance P in the zymosan-induced febrile response. Treatment with the NK1 antagonist SR140333B reduced the febrile response induced by zymosan, suggesting that this neuropeptide participates in this response. In models of acute visceral inflammation and nociception induced by zymosan, the internalization of NK1 receptors has been observed in neurons in lamina I and sympathetic preganglionic neurons, indicating that the release of substance P and activation of NK1 receptors are induced by this stimulus [39], [40]. These results support the hypothesis that zymosan induces substance P release from neurons.

We also analyzed ET-1, which has been shown to promote fever through ETB receptor activation [18]. An effective treatment with the ETB receptor antagonist BQ788 significantly reduced the febrile induced by the i.p. injected zymosan. In contrast, Kanashiro et al. [23] reported that BQ788 did not reduce the febrile response induced by i.a. zymosan. The inflammatory process is different in the joints and other sites of the body. For example, Griffiths et al. compared the effectiveness of 5-lipooxygenase inhibitors against zymosan-induced inflammation in the rat knee joint and peritoneal cavity [41]. An i.p. injection of zymosan induced a single initial peak of eicosanoid production, whereas the i.a. injection of this polysaccharide led to two different peaks: one initial peak and a later peak associated with leukotriene and prostaglandin production. The initial phase of higher permeability in the joint and peritoneal cavity was also differentially affected by leukotriene inhibitors. These results demonstrate that different mediators are involved in the inflammatory reaction that is induced by zymosan in the peritoneum and knee joint. Previous studies have also shown that the antibodies against adhesion molecules do not affect zymosan-induced inflammation in joints but reduced zymosan-induced peritonitis, suggesting that the characteristics of inflammation are site-specific [42]. It has been demonstrated that, specifically for the febrile response, the route of administration may have an important impact on the kind of mediators generated and their access to the central nervous system [43]. This may also be caused by the access of pyrogens to the cells bearing the specific Toll-like receptor involved. Voss et al. [43] demonstrated that the administration of synthetic RNA into the artificial subcutaneously implanted Teflon chambers, in contrast to LPS, had no pyrogenic activity or cytokine-inducing effects, whereas the i.p. or intra-arterial, and intramuscular injection caused a pronounced or moderated fever and cytokine induction, respectively. In the model of joint inflammation (localized inflammatory response) this might not be the case. The induction of the ET-1 synthesis by zymosan has been previously reported. Zymosan increased the levels of prepro-ET1 mRNA in rat knee joints [44]. The ETA and ETB receptor antagonist administration reduced edema formation, neutrophil influx, and TNF-α production in rat knee joints [45]. These results suggest that zymosan can induce the production of ET-1, at least locally. However, the central, rather than peripheral, production of ET-1 seems to be important for the febrile response [18]. In contrast with the i.a injection, the i.p. injection of zymosan might result in sufficient amounts of this pyrogen in the circulation; hence, the fever-related brain sites with an incomplete blood-brain barrier can be directly activated by this pyrogen [25] to produce ET-1 in the central nervous system. These studies and the present results suggest that different inflammatory sites can produce different mediators of inflammation, which may lead to varying inflammatory and febrile responses.

Notably, ET-1 also participates in the febrile response induced by the i.p. injected zymosan (present study) and LPS [16] but not polyinosinic:polycytidylic acid [28], suggesting that ET-1 participates in the febrile response induced by bacteria and fungus but not viruses.

Endogenous opioids also participate in the zymosan-induced febrile response. An i.c.v. injection of the MOR antagonist CTAP significantly reduced the febrile response induced by the i.p. injected zymosan. We previously found that eOPs participate in the febrile response that is induced by ET-1 and CRF but not prostaglandins [20]. Kanashiro et al. [24] reported that ET-1 and CRF do not participate in the febrile response induced by i.a. zymosan. In the present study, we evaluated whether eOPs are involved in the febrile response induced by i.a. zymosan. Surprisingly, the febrile response induced by i.a. zymosan, similar to i.p. administration, was reduced by the MOR antagonist CTAP. The CRF/ET-1 pathway is not involved in i.a. zymosan-induced fever [24], indicating that the eOPs are not released through the CRF or ET-1 during the febrile response; instead, they appear to be released through cytokines, such as TNF-α and IL-6 [20], [21].

The present results indicate that centrally produced prostaglandins, substance P, ET-1, and eOPs participate in the febrile response induced by an i.p. injection of zymosan. Although ET-1 does not appear to participate in the febrile response observed after the zymosan-induced knee joint inflammation, it appears to participate in the zymosan-induced fever after peritonitis.

Acknowledgments

This study was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Brazil (Grant No. 473873/2011-7). D. Fraga had a postdoctoral scholarship from REUNI, UFPR.

References

  • 1.

    Li S, Wang Y, Matsumura K, Ballou LR, Morham SG, Blatteis CM. The febrile response to lipopolysaccharide is blocked in cyclooxygenase-2(-/-), but not in cyclooxygenase-1(-/-) mice. Brain Res 1999;825:86–94. CrossrefGoogle Scholar

  • 2.

    Engblom D, Saha S, Engstrom L, Westman M, Audoly LP, Jakobsson PJ, et al. Microsomal prostaglandin E synthase-1 is the central switch during immune-induced pyresis. Nat Neurosci 2003;6:1137–8. CrossrefPubMedGoogle Scholar

  • 3.

    Saha S, Engstrom L, Mackerlova L, Jakobsson PJ, Blomqvist A. Impaired febrile responses to immune challenge in mice deficient in microsomal prostaglandin E synthase-1. Am J Physiol Regul Integr Comp Physiol 2005;288:R1100–7. CrossrefPubMedGoogle Scholar

  • 4.

    Engstrom L, Ruud J, Eskilsson A, Larsson A, Mackerlova L, Kugelberg U, et al. Lipopolysaccharide-induced fever depends on prostaglandin E2 production specifically in brain endothelial cells. Endocrinology 2012;153:4849–61. Web of ScienceCrossrefPubMedGoogle Scholar

  • 5.

    Steiner AA, Chakravarty S, Rudaya AY, Herkenham M, Romanovsky AA. Bacterial lipopolysaccharide fever is initiated via Toll-like receptor 4 on hematopoietic cells. Blood 2006;107:4000–2. PubMedCrossrefGoogle Scholar

  • 6.

    Lazarus M, Yoshida K, Coppari R, Bass CE, Mochizuki T, Lowell BB, et al. EP3 prostaglandin receptors in the median preoptic nucleus are critical for fever responses. Nat Neurosci 2007;10:1131–3. CrossrefPubMedWeb of ScienceGoogle Scholar

  • 7.

    Ushikubi F, Segi E, Sugimoto Y, Murata T, Matsuoka T, Kobayashi T, et al. Impaired febrile response in mice lacking the prostaglandin E receptor subtype EP3. Nature 1998;395:281–4. CrossrefPubMedGoogle Scholar

  • 8.

    Nakamura Y, Nakamura K, Morrison SF. Different populations of prostaglandin EP3 receptor-expressing preoptic neurons project to two fever-mediating sympathoexcitatory brain regions. Neuroscience 2009;161:614–20. PubMedWeb of ScienceCrossrefGoogle Scholar

  • 9.

    Rothwell NJ. CRF is involved in the pyrogenic and thermogenic effects of interleukin 1 beta in the rat. Am J Physiol 1989;256(1 Pt 1):E111–5. PubMedGoogle Scholar

  • 10.

    Strijbos PJ, Hardwick AJ, Relton JK, Carey F, Rothwell NJ. Inhibition of central actions of cytokines on fever and thermogenesis by lipocortin-1 involves CRF. Am J Physiol 1992;263(4 Pt 1):E632–6. PubMedGoogle Scholar

  • 11.

    Soares DM, Figueiredo MJ, Martins JM, Machado RR, Kanashiro A, Malvar Ddo C, et al. CCL3/MIP-1 alpha is not involved in the LPS-induced fever and its pyrogenic activity depends on CRF. Brain Res 2009;1269:54–60. CrossrefWeb of SciencePubMedGoogle Scholar

  • 12.

    Szelenyi Z, Szekely M, Balasko M. Role of substance P (SP) in the mediation of endotoxin (LPS) fever in rats. Ann N Y Acad Sci 1997;813:316–23. PubMedCrossrefGoogle Scholar

  • 13.

    Blatteis CM, Xin L, Quan N. Neuromodulation of fever. A possible role for substance P. Ann N Y Acad Sci 1994;741:162–73. CrossrefGoogle Scholar

  • 14.

    Reis RC, Brito HO, Fraga D, Cabrini DA, Zampronio AR. Central substance P NK(1) receptors are involved in fever induced by LPS but not by IL-1beta and CCL3/MIP-1alpha in rats. Brain Res 2011;1384:161–9. PubMedCrossrefGoogle Scholar

  • 15.

    Brito HO, Barbosa FL, Reis RC, Fraga D, Borges BS, Franco CR, et al. Evidence of substance P autocrine circuitry that involves TNF-alpha, IL-6, and PGE2 in endogenous pyrogen-induced fever. J Neuroimmunol 2016;293:1–7. CrossrefPubMedGoogle Scholar

  • 16.

    Fabricio AS, Silva CA, Rae GA, D’Orleans-Juste P, Souza GE. Essential role for endothelin ET(B) receptors in fever induced by LPS (E. coli) in rats. Br J Pharmacol 1998;125:542–8. CrossrefPubMedGoogle Scholar

  • 17.

    Fabricio AS, Rae GA, Zampronio AR, D’Orleans-Juste P, Souza GE. Central endothelin ET(B) receptors mediate IL-1-dependent fever induced by preformed pyrogenic factor and corticotropin-releasing factor in the rat. Am J Physiol Regul Integr Comp Physiol 2006;290:R164–71. CrossrefPubMedGoogle Scholar

  • 18.

    Fabricio AS, Rae GA, D’Orleans-Juste P, Souza GE. Endothelin-1 as a central mediator of LPS-induced fever in rats. Brain Res 2005;1066:92–100. PubMedCrossrefGoogle Scholar

  • 19.

    Blatteis CM, Xin L, Quan N. Neuromodulation of fever: apparent involvement of opioids. Brain Res Bull 1991;26:219–23. CrossrefPubMedGoogle Scholar

  • 20.

    Fraga D, Machado RR, Fernandes LC, Souza GE, Zampronio AR. Endogenous opioids: role in prostaglandin-dependent and -independent fever. Am J Physiol Regul Integr Comp Physiol 2008;294:R411–20. PubMedCrossrefGoogle Scholar

  • 21.

    Zampronio AR, Soares DM, Souza GE. Central mediators involved in the febrile response: effects of antipyretic drugs. Temperature (Austin) 2015;2:506–21. PubMedCrossrefGoogle Scholar

  • 22.

    Li S, Llanos QJ, Blatteis C. Thermal response to zymosan: the differential role of complement. Neuroimmunomodulation 2002;10:122–8. PubMedCrossrefGoogle Scholar

  • 23.

    Kanashiro A, Pessini AC, Machado RR, Malvar Ddo C, Aguiar FA, Soares DM, et al. Characterization and pharmacological evaluation of febrile response on zymosan-induced arthritis in rats. Am J Physiol Regul Integr Comp Physiol 2009;296: R1631–40. Web of SciencePubMedCrossrefGoogle Scholar

  • 24.

    Kanashiro A, Figueiredo MJ, Malvar Ddo C, Souza GE. Cytokines, but not corticotropin-releasing factor and endothelin-1, participate centrally in the febrile response in zymosan-induced arthritis in rats. Brain Res 2015;1610:12–9. Web of ScienceCrossrefPubMedGoogle Scholar

  • 25.

    Bastos-Pereira AL, Fraga D, Ott D, Simm B, Murgott J, Roth J, et al. Involvement of brain cytokines in zymosan-induced febrile response. J Appl Physiol 2014;116:1220–9. Web of ScienceCrossrefPubMedGoogle Scholar

  • 26.

    Gordon CJ. Thermal biology of the laboratory rat. Physiol Behav 1990;47:963–91. CrossrefGoogle Scholar

  • 27.

    Paxinos G, Watson C. The rat brain in extereotaxic coordinates. San Diego: Academic Press, 1998. Google Scholar

  • 28.

    Bastos-Pereira AL, Leite MC, Fraga D, Zampronio AR. Central mediators involved in the febrile response induced by polyinosinic-polycytidylic acid: lack of involvement of endothelins and substance P. J Neuroimmunol 2015;278:100–7. Web of ScienceCrossrefPubMedGoogle Scholar

  • 29.

    Consiglio AR, Lucion AB. Technique for collecting cerebrospinal fluid in the cisterna magna of non-anesthetized rats. Brain Res Brain Res Protoc 2000;5:109–14. PubMedCrossrefGoogle Scholar

  • 30.

    Leite AC, Cunha FQ, Dal-Secco D, Fukada SY, Girao VC, Rocha FA. Effects of nitric oxide on neutrophil influx depends on the tissue: role of leukotriene B4 and adhesion molecules. Br J Pharmacol 2009;156:818–25. PubMedWeb of ScienceCrossrefGoogle Scholar

  • 31.

    Vale ML, Benevides VM, Sachs D, Brito GA, da Rocha FA, Poole S, et al. Antihyperalgesic effect of pentoxifylline on experimental inflammatory pain. Br J Pharmacol 2004;143:833–44. CrossrefPubMedGoogle Scholar

  • 32.

    Gemmell DK, Cottney J, Lewis AJ. Comparative effects of drugs on four paw oedema models in the rat. Agents Actions 1979;9:107–16. PubMedCrossrefGoogle Scholar

  • 33.

    Cremeans-Smith JK, Newberry BH. Zymosan: induction of sickness behavior and interaction with lipopolysaccharide. Physiol Behav 2003;80:177–84. PubMedCrossrefGoogle Scholar

  • 34.

    Underhill DM, Ozinsky A, Hajjar AM, Stevens A, Wilson CB, Bassetti M, et al. The Toll-like receptor 2 is recruited to macrophage phagosomes and discriminates between pathogens. Nature 1999;401:811–5. CrossrefPubMedGoogle Scholar

  • 35.

    Gantner BN, Simmons RM, Canavera SJ, Akira S, Underhill DM. Collaborative induction of inflammatory responses by dectin-1 and Toll-like receptor 2. J Exp Med 2003;197:1107–17. PubMedCrossrefGoogle Scholar

  • 36.

    Morimoto A, Murakami N, Nakamori T, Sakata Y, Watanabe T. Possible involvement of prostaglandin E in development of ACTH response in rats induced by human recombinant interleukin-1. J Physiol 1989;411:245–56. CrossrefPubMedGoogle Scholar

  • 37.

    Cao C, Matsumura K, Yamagata K, Watanabe Y. Cyclooxygenase-2 is induced in brain blood vessels during fever evoked by peripheral or central administration of tumor necrosis factor. Brain Res Mol Brain Res 1998;56:45–56. CrossrefPubMedGoogle Scholar

  • 38.

    Rummel C, Sachot C, Poole S, Luheshi GN. Circulating interleukin-6 induces fever through a STAT3-linked activation of COX-2 in the brain. Am J Physiol Regul Integr Comp Physiol 2006;291:R1316–26. PubMedCrossrefGoogle Scholar

  • 39.

    Landau AM, Yashpal K, Cahill CM, St Louis M, Ribeiro-da-Silva A, Henry JL. Sensory neuron and substance P involvement in symptoms of a zymosan-induced rat model of acute bowel inflammation. Neuroscience 2007;145:699–707. Web of SciencePubMedCrossrefGoogle Scholar

  • 40.

    Honore P, Kamp EH, Rogers SD, Gebhart GF, Mantyh PW. Activation of lamina I spinal cord neurons that express the substance P receptor in visceral nociception and hyperalgesia. J Pain 2002;3:3–11. CrossrefPubMedGoogle Scholar

  • 41.

    Griffiths RJ, Li SW, Wood BE, Blackham A. A comparison of the anti-inflammatory activity of selective 5-lipoxygenase inhibitors with dexamethasone and colchicine in a model of zymosan induced inflammation in the rat knee joint and peritoneal cavity. Agents Actions 1991;32:312–20. CrossrefGoogle Scholar

  • 42.

    van de Langerijt AG, Huitinga I, Joosten LA, Dijkstra CD, Van Lent PL, van den Berg WB. Role of beta 2 integrins in the recruitment of phagocytic cells in joint inflammation in the rat. Clin Immunol Immunopathol 1994;73:123–31. PubMedCrossrefGoogle Scholar

  • 43.

    Voss T, Rummel C, Gerstberger R, Hubschle T, Roth J. Fever and circulating cytokines induced by double-stranded RNA in guinea pigs: dependence on the route of administration and effects of repeated injections. Acta Physiol (Oxf) 2006;187: 379–89. PubMedCrossrefGoogle Scholar

  • 44.

    Conte FP, Menezes-de-Lima O, Jr., Verri WA, Jr., Cunha FQ, Penido C, Henriques MG. Lipoxin A(4) attenuates zymosan-induced arthritis by modulating endothelin-1 and its effects. Br J Pharmacol 2010;161:911–24. PubMedWeb of ScienceCrossrefGoogle Scholar

  • 45.

    Conte Fde P, Barja-Fidalgo C, Verri WA, Jr., Cunha FQ, Rae GA, Penido C, et al. Endothelins modulate inflammatory reaction in zymosan-induced arthritis: participation of LTB4, TNF-alpha, and CXCL-1. J Leukoc Biol 2008;84:652–60. PubMedWeb of ScienceCrossrefGoogle Scholar

About the article

Received: 2017-04-24

Accepted: 2017-08-15

Published Online: 2017-10-05

Published in Print: 2017-11-27


Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.

Research funding: None declared.

Employment or leadership: None declared.

Honorarium: None declared.

Competing interests: The funding organization(s) played no role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the report for publication.


Citation Information: Journal of Basic and Clinical Physiology and Pharmacology, Volume 28, Issue 6, Pages 555–562, ISSN (Online) 2191-0286, ISSN (Print) 0792-6855, DOI: https://doi.org/10.1515/jbcpp-2017-0061.

Export Citation

©2017 Walter de Gruyter GmbH, Berlin/Boston.Get Permission

Comments (0)

Please log in or register to comment.
Log in