[Change of angiotensin system activity and the effects of corticosteroid on it in asthmatic guinea pigs].

OBJECTIVE

To investigate the role of angiotensin system(ATs) and effect of corticosteroid on ATs activity at the onset of asthma.

METHODS

After establishing asthmatic model of guinea pig by intraperitoneal injection with ovalbumin to sensitize and inhalation with the same sensitizer 3 weeks later to induce asthma attack, the levels of angiotensin(AT) I and AT II and the activity of angiotensin converting enzyme(ACE) were measured respectively in extractive fluid of chopped lung tissue, bronchial alveolar lavage fluid (BALF) and plasma (ACE activity in serum) in three groups of experimental guinea pigs including asthmatic group, control group and corticosteroid group.

RESULTS

In the chopped lung tissue and BALF, the AT I, AT II levels and the ACE activity in the asthmatic group were significantly higher than that in the control group(P < 0.01), however, they did not differ significantly each other in plasma in three groups(P > 0.05). In corticosteroid group, the levels of AT I, AT II and ACE activity were significantly decreased in the BALF compared with that in the asthmatic group(P < 0.01).

CONCLUSION

The results suggest that the lung tissue may have a local angiotensin system that may be activated and play a role in asthma attack, and the inhibition of ATs activity may be one of the mechanisms in the effects of inhaled corticosteroid on prevention and control of asthma.