The aim of the present study was to evaluate the antiinflammatory activity of preelafin, an elastasespecific inhibitor, in lipopolysaccharide (LPS)induced acute lung inflammation. C57BL/6 mice were pretreated intranasally with recombinant human preelafin or vehicle only. One hour later, they were instilled intranasally with LPS (2 g/mouse). Animals were sacrificed 6 hours after LPS instillation and bronchoalveolar lavage (BAL) was performed with three 1- ml aliquots of saline. LPS induced a lung inflammation characterised by a 100-fold increase in BAL neutrophils compared to control animals (265.8±54.5 103 and 2.4±1.3 103 neutrophils/ml, respectively). Preelafin dosedependently reduced the neutrophil influx in the lung alveolar spaces by up to 84%. No elastase activity was detectable in all BAL fluids tested. Preelafin also reduced significantly LPSinduced gelatinase activity, as shown by zymography, and BAL macrophage inflammatory protein-2 (MIP-2) and KC levels, two potent neutrophil attractants and activators. Moreover, preelafin also significantly reduced mRNA levels of the three members of the IL-1 ligand family, namely IL-1α, IL-1β and IL-1 receptor antagonist (IL-1Ra), type II IL-1 receptor, and TNFα as assessed in whole lung tissue by RNase protection assay. Thus, preelafin may be considered as a potent antiinflammatory mediator.
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