不同预适应对海水浸泡束缚大鼠应激性溃疡的影响

Effect of different preconditionings on stress ulcer induced by seawater immersion and restriction in rats

目的:建立束缚及海水浸泡致应激性溃疡的动物模型,探讨预适应对应激性溃疡的作用机制及不同应激时间对溃疡影响。方法:Wistar雄性大鼠60只均分成6组:A组为正常对照组,B组为直接应激组,C组为预适应Ⅰ组,D组为预适应Ⅱ组,E组为预适应Ⅲ组,F组为雷尼替丁组。C、D、E组预适应时间分别为0.5h/d、1h/d、1h/d连续5d,F组雷尼替丁灌胃,每日2ml/100g,连续6d。应激:B、C、D、F组海水浸泡8h,E组海水浸泡10h。采用放射免疫法测定应激性溃疡大鼠血清内皮素和6-酮-前列腺素F1α水平变化,通过Guth法评定溃疡指数,溃疡局部胃组织行病理组织学检查。结果:C组、D组及F组血清内皮素水平显著低于B组(P<0.01,P<0.05,P<0.01);C组、D组及F组血清6-酮-前列腺素F1α水平显著高于B组(P<0.01,P<0.05,P<0.01);C组、D组及E组溃疡指数显著低于B组(P<0.01,P<0.05,P<0.01);C组、D组及F组病理较B组改善。E组与B组各指标无明显差别。结论:预适应可有效减轻大鼠应激性溃疡,但应激时间太长可抵消预适应的保护作用。

Objective：To establish a stress ulcer model by seawater immersion and restriction in rats, and to investigate the mechanism of preconditioning on stress ulcer and the effect of different stressing periods on the ulcer. Methods： A total of 60 male Wistar rats were equally divided into 6 groups , namely, the normal control group （Group A） , direct stress group（Group B）, precondition group Ⅰ （Group C）, precondition groupⅡ （Group S）, precondition group Ⅲ （Group E）, and ranitidine group （Group F）. Precondition peroids of C,13, E groups were 0.5 h/d, 1 h/d, and 1 h/d, respectively, for 5 days. Stress time in E group was 10 h,and in B,C,D,and F groups were 8 h. Radioimmunoassay was used to determine the sera levels of endothelin （ET） and 6-dk-dPGF1α in rats. Ulcer index was calculated by Guth method; the ulcer lesion tissues were collected for further pathological examination. Results： The sera ET levels in group C, D and F were lower than those in group B（P〈0.01, P〈0.05,and P〈0.01, respectively）. The sera 6-dk-dPGF1α levels in group C, D and F were significantly higher than those in group B（P〈0.01,P〈0.05,and P〈0.01, respectively）. The ulcer indices in group C, D and F were significantly lower than those in group B （P〈0.01 ,P〈0.05 ,and P〈0.01, respectively）. The pathological results were improved in group C, D, and F compared with those in group B. Conclusion： Preconditioning can effectively reduce the rat stress ulcer, but long-time stressing may offset the protective effect of precondition.