幽门螺杆菌及其相关细胞因子对胃上皮细胞凋亡的调控及相关机制

目的研究幽门螺杆菌（Hp）及其相关细胞因子对胃上皮细胞凋亡的影响,以探讨Hp的致病机理。方法以人胃永生化上皮细胞株（GES-）和人胃癌细胞株（AGS）作为研究对象。流式细胞术检测Hp毒力菌株（NCTC11637）单独及分别联合Hp相关细胞因子白细胞介素（IL）-1β、IL-8及IL-10]对两种细胞系凋亡的影响;检测IL-1β、IL-8及IL-10对外源性Fas配体（FasL）诱导的两种细胞系凋亡的影响。逆转录-聚合酶链反应检测Hp及其相关细胞因子（IL-1β、IL-8及IL-10）对两种细胞系FasmRNA基础表达水平的影响。结果（1）Hp能诱导GES-1和AGS细胞凋亡增加113．0％和47．0％（均P〈0．05）;IL-1β、IL-10能抑制Hp诱导的GES-1（29．6％、25．8％）和AGS（19．7％、21．1％）细胞凋亡（均P〈0．05）;IL-8能增强Hp诱导的GES-1细胞凋亡（19．9％,P〈0．05）。（2）Hp能上调GES-1和AGS细胞FasmRNA基础表达水平（89．0％和36．0％,P〈0．05）;IL-1β、IL-10对两种细胞FasmRNA基础表达无显著影响（P〉0．05）;IL-8能上调GES-1（33．0％）细胞FasmRNA基础表达（P〈0．05）。（3）IL-1β、IL-10能抑制FasL诱导的GES-1（30．3％、32．5％）和AGS（44．2％、51．5％）细胞凋亡（P〈0．05）;IL-8能增强FasL诱导的GES。1细胞凋亡（100％,P〈0．05）。结论Hp可通过上调Fas受体表达直接介导胃上皮细胞凋亡。Hp相关细胞因子IL-8可能通过上调Fas受体表达来增强Hp诱导的胃上皮细胞凋亡;IL—1β和IL-10可能通过其他机制来抑制Hp诱导的胃上皮细胞凋亡。

Effects of Helicobacter pylori and Helicobacter pylori-related cytokines on apoptosis of gastric epithelial cells and mechanisms thereof

OBJECTIVE: To investigate the influence of Helicobacter pylori (H. pylori) and H. pylori-related cytokines on the apoptosis of gastric epithelial cells and mechanisms thereof. METHODS: (1) Human gastric cancer cells of the line AGS and human gastric epithelial cells of the line GES-1 were cultured as control group, or incubated with H. pylori alone or H. pylori in combination with exogenous cytokines: interleukin (IL)-1beta, IL-8, or IL-10 for 24 hours. Then flow cytometry (FCM) was used to determine the rate of apoptosis. (2) The GES-1 and AGS cells were incubated with H. pylori for 24 hours and exogenous cytokines for 2 hours respectively. Then RT-PCR was used to examine the level of Fas mRNA expression. (3) Another GES-1 and AGS cells were cultured as control group, or incubated with FasL alone or FasL + exogenous cytokine for 2 hours (incubated with IL-1beta, IL-8, or IL-10 for 2 hours before being added with FasL). Then FCM was used to detect the apoptosis rate. RESULTS: (1) In comparison to the apoptosis level of control group, H. pylori induced an increase in the apoptosis rate of GES-1 and AGS cells by 113.0% and 47.0% respectively (both P < 0.05). The H. pylori-induced apoptosis rates of GES-1 cells (by 29.6% or 25.8%) and AGS cells (by 19.7% or 21.1%) were reduced by IL-1beta or IL-10 (all P < 0.05). IL-8 increased the H. pylori-induced apoptosis level of GES-1 cells by 19.9% (P < 0.05). (2) In the baseline status, both GES-1 and AGS cells showed Fas mRNA expression. The Fas mRNA expressions of the GES-1 and AGS cells incubated with H. pylori were increased by 89.0% and 36.0% respectively (both P < 0.05) in comparison to that of the control group. IL-1beta and IL-10 had no significant effect on the basal Fas mRNA expressions in both GES-1 and AGS cells (all P > 0.05). IL-8 up-regulated the basal Fas mRNA expression level of the GES-1 cells by 33.0% (P < 0.05). (3) IL-1beta and IL-10 inhibited the FasL-induced apoptosis rate of the GES-1 cells (by 30.3% and 32.5% respectively) and AGS cells (by 44.2% and 51.5% respectively) (all P < 0.05). IL-8 enhanced the FasL-induced apoptosis level of the GES-1 cells by 100% (P < 0.05). CONCLUSION: The gastric epithelium apoptosis induced by H. pylori may be in association with Fas receptor. IL-8 may enhance the H. pylori-induced apoptosis by up-regulating the Fas receptor expression. IL-1beta and IL-10 may modulate the apoptosis through other mechanisms.