Protective effect of gastrin-releasing peptide receptor antagonist in carrageenan-induced pleural inflammation in rats.

We report the effects of the gastrin-releasing peptide (GRP) receptor antagonist RC-3095 in an acute inflammation model induced by carrageenan. Male Wistar rats received saline or saline containing 2% lambda-carrageenan into the pleural cavity, with some also receiving RC-3095 3 mg/kg subcutaneously, immediately after surgery. Four hours later, the rats were killed and pleural exudate was obtained for evaluation of total cell count, lactate dehydrogenase activity, total protein, cytokines analysis and nitrite/nitrate concentrations; myeloperoxidase (MPO) activity and oxidative stress were evaluated in the lung. RC-3095 exhibited pronounced anti-inflammatory actions by inhibition of leukocyte influx and blockade of MPO, nitrite/nitrate and cytokine levels. Moreover, the results showed that RC-3095 elicits action against oxidative damage in lipids and proteins, as well as increasing cell viability. The present findings suggest that GRP plays a role in acute inflammation that can be related with the reduction of oxidative damage and that it could be effective in therapeutic applications.