血管紧张素Ⅱ拮抗剂在大鼠应激性溃疡中的作用

Role of angiotensin Ⅱ antagonist in the formation of stress ulcer in rats

目的:探讨血管紧张素Ⅱ拮抗剂在大鼠应激性溃疡(SU)中的作用.方法:水浸束缚应激后,肉眼计算胃黏膜溃疡指数(UI);取动脉血和胃液做血气分析计算胃黏膜内pH值;采用放射免疫方法检测血栓素B2(TXB2)和6-酮前列腺素F1α(6-K);观察胃组织病理形态学变化.结果:管紧张素Ⅱ拮抗剂组与阴性对照组比较,pH值、6-K水平显著升高(4.82±0.31vs4.53±0.11,P=0.026;974.95±109.11ng/Lvs654.50±221.31ng/L,P<0.01),而TXB2,UI显著降低(48.53±8.26ng/Lvs98.18±39.24ng/L,P<0.01;36.13±6.49vs69.00±33.27,P<0.01).病理形态学观察,血栓形成减少.血管紧张素Ⅱ拮抗剂组与奥美拉唑组比较,除6-K(974.95±109.11ng/Lvs737.61±96.10ng/L,P<0.05)外,其他数据无统计学差异.结论:血管紧张素Ⅱ拮抗剂通过舒张血管,增加胃黏膜血流量起到保护胃黏膜的作用,其机制可能是减轻肾上腺髓质对应激的反应,抑制由应激引起的儿茶酚胺的合成和释放,促进前列腺素的分泌.

AIM： To investigate the role of angiotensins Ⅱ antagonist in the occurrence and development of stress ulcer in rats. METHODS： The ulcer index （UI） was observed after water immersion-restaint stress （WRS）, and the levels of thromboxane B2 （TXB2） and 6-ketoprostaglandin F1 alpha （6-K） were measured by radioimmunoassay. The gastric mucosal pH value was detected and histopathological changes were observed. RESULTS： In comparison with those in the negative controls, the gastric mucosal pH value and 6-K level were significantly increased in the antagonist group （4.82 ± 0.31 vs 4.53 ± 0.11, P = 0.026; 974.95 ± 109.11 ng/L vs 654.50 ± 221.31 ng/L, P 〈 0.01）, but the TXB2 level and UI were significant decreased （48.53 ± 8.26 ng/L vs 98.18 ± 39.24 ng/L, P 〈 0.01; 36.13 ± 6.49 vs 69.00 ± 33.27, P 〈 0.01）. Meanwhile, thrombosis was also decreased in the antagonist group. The level of 6-K was significantly different between the antagonist and positive control group （974.95 ± 109.11 ng/L vs 737.61 ± 96.10 ng/L, P 〈 0.05）, but the pH value, UI and TXB2 level had no marked difference between the two groups. CONCLUSION： Pretreatment of angiotensins Ⅱ antagonists can protect gastric mucosa by dilatation of blood vessel and increase of blood flow, and the mechanism may be associated with the inhibition of corticosterone production and prostaglandin E2 secretion.