Activation of alveolar phospholipase A2 after hydrochloric acid aspiration in rats.
PURPOSE: The present study was carried out to determine phospholipase A2 (PLA2) activity in the bronchoalveolar lavage fluid (BALF) in rats subjected to HCI aspiration. MATERIALS AND METHODS: Rats were allocated into one of five groups. Groups H-1 and H-3 received instillation of HCI into lungs. Groups S-1 and S-3 received saline instead of HCI. Group C received no instillation. BAL was performed according to the protocol, that is, 1 hour after the instillation in groups H-1 and S-1, 3 hours after the instillation in groups H-3 and S-3, and arbitrarily in group C. Obtain BALF was analyzed for the protein concentration, PLA2 activity, and the molecular mass of PLA2. RESULTS: The protein concentration in BALF showed an increase in groups H-1 and H-3. PLA2 activity decreased in group H-1, but increased in group H-3, compared with groups S-1 and S-3, respectively. PLA2 in groups C and H-1 revealed a high molecular mass (HM), but that in group H-3 revealed a low molecular mass (LM). CONCLUSIONS: There is an increase in the alveolar LM-PLA2 at inflammatory phase after HCI aspiration, suggesting the pathophysiologic role of LM-PLA2 in the acute lung injury.