幽门螺杆菌cagA基因对胃癌细胞影响

目的观察幽门螺杆菌（Hp）野生株与cagA基因同源缺失突变株对人胃癌细胞株BGC823的细胞增殖和凋亡的影响,探讨与Hp毒力基因cagA相关的细胞水平的毒性效应。方法将幽门螺杆菌野生株与cagA基因缺失突变株与BGC823细胞共培养,分别在6,12,24和48 h观察细胞形态学变化,采用四甲基偶氮噻唑蓝（MTT）比色法检测细胞增殖活性,流式细胞仪检测细胞凋亡情况。结果野生株和突变株Hp攻击BGC823细胞6 h,即可引起细胞的形态学变化,48 h时均可观察到细胞形态呈分散及蜂鸟样改变（细胞拉伸）。MTT法检测显示,野生株对BGC823细胞增殖具有抑制作用,而缺失cagA基因的突变株可刺激细胞增殖,且在24,48 h的2个时间点上均高于对照组和野生株组（P〈0.05）。流式细胞分析显示,在攻击BGC823细胞48 h后,野生株和突变株均可引起细胞凋亡,凋亡率高于对照组（P〈0.05）,2个实验组的凋亡率差异无统计学意义。结论Hp作用后细胞呈分散和蜂鸟样改变（伸长）并不是cagA基因特有的细胞学效应;cagA基因是Hp抑制细胞增值所必需的元素;cagA基因的有无对Hp致凋亡效应的影响不大,在Hp致细胞凋亡的效应中作用可能有限。

Effects of cagA gene of helicobacter pylori on BGC823 cells

objective To observe the effects of a cagA-deleted mutant strain of Chinese H.pylori on the phenotypes,proliferation and apoptosis in human gastric cancer cell line BGC823 in vitro,and to determine the cytotoxicity of cagA,one of the virulence gene of H.pylori.Methods BGC823 cells were co-cultured with the wild type H.pylori and the isogenous mutant,which were called the wild tue strain group and the mutant stain group,respectively.The cell phenotype was observed at 6,12,24 and 48h and the cellular proliferation was examined by methyl thiazolyl tetrazolium(MTT) method.The induction of apoptosis was determined by flow cytometry.Results The changes of cell morphology were observed when BGC823 cells were co-cultured with H.pylori for 6 hours,and cell scatterring and hummingbird morphology(cell elongation) were presented after co-cultured for 48 hours in both groups.The MTT assay showed that the viability of BGC823 cells was inhibited in the wild type strain group,while was significant higher in the mutant strain group than that of the control group and the wild type strain group when co-cultured with H.pylori for 24 and 48 hours,respectively.As demonstrated by flow cytometry,the apoptotic rate in both the wild type and the mutant group was higher than that of control group(P<0.05),but there was no difference between the two groups treated with H.pylori. Conclusions Cell scatterring and hummingbird phenotype(cell elongation) were not the cell morphology characteristics specific related to the cagA gene after treated with H.pylori;The cagA gene may play the crucial role in H.pylori's actions of inhibiting cellular proliferation;The cagA gene may have the only limited effects on the cellular apoptosis induced by H.pylori.