Effect of dexamethasone on endothlin- 1 in asthmatic guirfea pigs

The levels of endothelin-1 (ET- 1 ) were determined by radioimmunoassay respectively in extractive fluid of chopped lung tissue, bronchoalveolar lavage fluid (BALF) and plasma in guinea pig models of asthma (asthma group), pretreated asthmatic guinea pigs with dexamethasone (Dex group) and control group to investigate the role of ET-1 in bronchial asthma and the effects of corticosteroid. Tile results showed: in asthma group, the levels of ET-1 in living lung tissue, Plasma, BALF were respectively 1 .50 0.23ng/g, 19.46 3.94 and 3.08 0.54ng/L which were significantly higher than that in control group (they were respectively 1 .07 0. 13ng/g, 11.74 4.21, 1 .84 0.41ng/ L ). However, dexamethasone significantly lower (P0.05), but uncompletely attenuated in Dex group (the levels were 1 .08 0.33ng/g, 14.2 4. 15, 2.10 0.60ng/L, respectively). The results suggest: ET-1 may play a important role in the development and deterioration of asthma, and corticosteroid inhibits the release of ET-1 whigs, might be one of mechanism of its therapeutic effects in asthma.