幽门螺杆菌感染对胃黏膜环氧合酶表达的影响

Expression of cyclooxygenase in Helicobacter pylori induced gastritis in mice

目的评估幽门螺杆菌(Hp)急、慢性感染对小鼠胃黏膜环氧合酶(COX)表达的影响。方法清洁级BALB／C小鼠共40只,分为阴性对照组(10只)予0．4 ml生理盐水灌喂,急性感染组(10只)予 0．4 ml Hp菌液灌喂,共5 d,该两组小鼠在最后一次灌喂后2周处死;另20只小鼠予0．4 ml Hp菌液灌喂,共5 d,在最后一次灌喂2个月后将小鼠均分为两组,治疗组予克拉霉素按每天13．5 mg／kg分2次灌喂,连续7 d(本组有1只小鼠死亡);慢性感染组予生理盐水,1个月后分别处死两组动物。取胃黏膜标本, 用免疫组化半定量法测定上述各组胃窦黏膜COX-1及COX-2的蛋白表达。结果四组小鼠胃黏膜小凹上皮均可见COX-1蛋白表达,各组阳性率差异无统计学意义(P>0．05)。与阴性对照组相比,急、慢性感染组COX-2蛋白表达均明显增加,其中慢性感染组治疗前COX-2阳性率明显高于急性感染组。慢性感染组治疗后阳性率与治疗前相比有所下降,但差异无统计学意义(P>0．05)。结论 Hp感染导致胃黏膜COX-2表达增加,对COX-1表达无明显作用,清除Hp后COX-2表达仍高于正常。

Objective To investigate the effects of Helicobacter pylori （H. pylori） infection on cyclooxygenase （COX） expression in mice gastric mucosa. Methods Forty 7-weeks old SPF BALB/C mice were divided into four groups. Mice in the acute infected group were inoculated orally with H. pylori （Sydney Strain 1） liquid 0.4 ml （1 × 10^9CFC） per mouse every＇ day for five days, while the mice in control group were given saline. Two weeks after the last bacteria inoculation, all mice were sacrificed. Another 20 mice were inoculated orally with H. pylori liquid every day for five days. Two months after infection of H. pylori, 20 mice were equally divided into two groups, the eradication group and chronic infection group. Mice in the eradication group were administered with elarithromyein （13.5 mg· kg^-1 · d^-1） twice per day for one week （one mouse died）. Meanwhile, mice in the chronic infection group were given saline. All mice were killed one month after the last administration of clarithromyein or saline. The gastric mueosa was taken for detecting COX-1 and COX-2 protein by immunohistoehemieal method. Results COX-1 was expressed in mice epithelial cells of gastric mucosa in all four groups. There were no significant differences in positive rates of COX-1 among four groups. COX-2 protein expressions were increased in either acute or chronic H. pylori infection groups as compared with negative control group. Before H. pylori eradication, the COX-2 positive rate in chronic infection group was apparently higher than that in acute infection group. In chronic infection group, the positive rate was slightly decreased after eradication compared with that before eradication （P〉0. 05）. Conclusion H. pylori infection induces the elevation of COX-2 but not COX-1 expression in mice gastric mucosa. The expression of COX-2 in epithelial cells remained high even after H. pylori eradication.