幽门螺杆菌诱导胃粘膜上皮细胞凋亡与Bax蛋白的表达

Gastric epithelial apoptosis induced by Helicobacter pylori and its relationship with Bax protein expression

目的观察幽门螺杆菌(Hp)感染诱导胃粘膜上皮细胞凋亡与Bax 蛋白表达的关系,探讨 Hp 诱导胃粘膜上皮细胞凋亡的机制。方法采用脱氧核糖核酸末端转移酶介导的缺口末端标记(TUNEL)技术原位观察和比较73例慢性胃炎患者胃粘膜上皮细胞凋亡情况,对其中50例 Hp 阳性患者 Hp 根除前后胃粘膜上皮细胞凋亡的变化进行检测;并采用免疫组织化学染色检测 Bax 蛋白表达变化。结果 Hp 阳性患者胃粘膜上皮细胞凋亡指数为12.8%,明显高于 Hp 阴性者(3.6%)(t=6.64,P<0.01);Hp 根除后胃粘膜上皮细胞凋亡指数(4.4%)较治疗前明显降低(12.5%,t=5.39,P<0.01),而持续阳性者凋亡指数无明显降低,Hp阳性患者胃粘膜上皮细胞 Bax 蛋白表达率为62.3%,显著高于Hp 阴性者(35.0%,x^2=4.36,P<O.05);Bax 蛋白表达阳性的 Hp 阳性患者在 Hp 根除后 Bax 阳性细胞密度显著减少(t=3.18,P<0.01),而 Hp 未被根除者 Bax 阳性细胞密度无明显变化。结论 Hp 感染可诱导胃粘膜上皮细胞凋亡,这可能是 Hp 参与胃癌发生的重要机制之一;Hp 感染可促进 Bax 蛋白表达增加,这可能是 Hp 感染诱导胃粘膜上皮细胞凋亡的机制之一。

AIM To study the relationship between gastric epithelial apoptosis induced by Helicobacter pylori(Hp)and Bax protein expression,and analyze the mechanisms of Hp infection induced gastric epithelial cell apoptosis and the role of Hp in the development of gastric diseases. METHODS Endoscopic mucosal biopsies were taken in 73 of with chronic gastritis.Using terminal deoxynucleotidyl transferase-mediated nick end labeling(TUNEL)technique and immunohistochemical staining,we observed the apoptotic cells and Bax protein expression in situ in Hp negative gastric mucosa and Hp positive gastric mucosa before and after Hp eradication. RESULTS The apoptotic index of gastric epithelial in the patients infected with Hp(12.8%)was significantly higher than that of Hp negative gastric epithelial(with apoptotic index 3.6%,t=6.64,P<0.01).After eradication of Hp with triple therapy,the apoptotic index fell from 12.5% to 4.4% (t=5.39,P<0.01).In the persisting Hp infected patients,the apoptotic index was not statistically decreased.The positive rate of Bax protein of gastric epithelial in the patients infected with Hp(62..3%) was significantly higher than that of Hp negative gastric epithelial (35.0%,X^2=4.36,P<0.05). After eradication of Hp with triple therapy,the positive cell density was statistically decreased(t=3.18, P<0.01).In the persisting Hp infected patients,the positive cell density was not statistically decreased. CONCLUSION Hp induces gastric epithelial apoptosis in vivo.Hp increases the expression of Bax protein,which may be one of the mechanisms by which Hp promotes gastric epithelial apoptosis.