Efeito da prednisolona sobre o processo inflamatório e no diâmetro alveolar em enfisema elastase induzido em ratos

Abstract

Glucocorticoids, as prednisolone, are used for a variety of inflammatory conditions, including asthma and pulmonary emphysema. However its mechanism of action and clinical use are still controversial.To evaluate the acute inflammatory response, tissue damage and nitric oxide in elastase-induced emphysema in rats after prednisolone treatment. 32 male rats were divided in four groups (n=8): Control (C), Emphysema (E), Prednisolone (P), Emphysema+Prednisolone (EP). Groups C and P received intratracheal instillation of 0.2 ml of saline and groups E and EP received instillation of 0.2 ml of porcine pancreatic elastase to induce emphysema. Prednisolone was administered (5mg/kg) in groups P and EP and vehicle in groups C and E. The administrations were performed once a day, by gavage, for 25 days. After sacrifice, lungs were removed for evaluation of alveolar diameter (Lm), quantification of leukocytes and nitric oxide in bronchoalveolar lavage.Comparing the elastase group with the control group, there was a significant increase in the alveolar airspace enlargement in the group with emphysema. However, comparing the control group with emphysema group treated with prednisolone, the treatment did not show significant reduction in the alveolar airspace enlargement. The number of leukocytes and nitric oxide level in BALF did not show statistically significant difference between groups.Despite widespread clinical use of corticosteroids in respiratory diseases, there was no direct protective effect on reducing the mean linear intercept of alveolar emphysema treated animals, suggesting further studies related to its mechanism of action and on its clinical use in patients with emphysema.