豚鼠支气管哮喘时血管紧张素系统的变化及糖皮质激素对其的作用

Change of Angiotensin System Activity and the Effects of Corticosteroid on It in Asthmatic Guinea Pigs

目的通过实验性哮喘豚鼠的肺组织、支气管肺泡灌洗液 (BALF)和血浆中的血管紧张素系统 (ATs)的变化，探讨 ATs与哮喘发病的关系以及吸入糖皮质激素对其的作用。方法将 27只豚鼠随机分为哮喘组 (向豚鼠腹腔内注射含有卵清蛋白的致敏剂致敏， 3周后，经超声雾化吸入 1％卵清蛋白气雾剂诱发豚鼠哮喘 )、激素组 (吸入卵清蛋白前，预先吸入 40 mg/dl地塞米松 20 min，余同哮喘组 )和对照组 (以等量生理盐水代替卵清蛋白 )，每组 9只，分别检测它们的肺切碎活组织、 BALF和血浆中的血管紧张素 I(ATⅠ )、血管紧张素Ⅱ (ATⅡ )水平和血清血管紧张素转换酶 (ACE)的活性。结果哮喘组肺切碎活组织、 BALF中 ATⅠ、 ATⅡ水平及 ACE活性均较对照组显著升高 (P< 0 01)；激素组显示糖皮质激素可使 BALF中 ATs各成分降低，但三组间血浆 ATⅠ、 ATⅡ水平和血清 ACE活性比较，差异均无显著性。结论肺组织可能存在局部 ATs，该系统在哮喘急性发作时被活化，并参与哮喘发病的病理生理过程。 ATⅡ由局部产生，但可能只在局部起作用。吸入糖皮质激素可抑制 ATs活性而起到保护肺、抑制哮喘发作的作用。

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 ATⅡ 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 ATⅠ， ATⅡ 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 ATⅠ ,ATⅡ 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 inhalled corticosteroid on prevention and control of asthma.