氯化钠和幽门螺杆菌空泡毒素对细胞因子表达及细胞活力的影响。
Effect of NaCl and Helicobacter pylori vacuolating cytotoxin on cytokine expression and viability.
作者信息
Sun Juan, Aoki Kazuo, Zheng Jin-Xu, Su Bing-Zhong, Ouyang Xiao-Hui, Misumi Junichi
机构信息
Department of Public Health and Hygiene(II), Faculty of Medicine, Oita University Oita 879-5593, Japan.
出版信息
World J Gastroenterol. 2006 Apr 14;12(14):2174-80. doi: 10.3748/wjg.v12.i14.2174.
AIM
To determine whether Helicobacter pylori (H pylori) vacuolating cytotoxin (VacA) regulates release of pro-inflammatory cytokines (IL-1beta, IL-8, TNF-alpha, and IL-6) or alters gastric epithelial cell viability and to determine whether NaCl affects these VacA-induced changes.
METHODS
Vacuolating activity was determined by measuring the uptake of neutral red into vacuoles of VacA-treated human gastric epithelial (AGS) cells. AGS cell viability was assessed by direct cell counting. Specific enzyme-linked immunosorbent assays (ELISA) and reverse transcriptase-polymerase chain reaction(RT-PCR) were performed to examine the effects of H pylori VacA and NaCl on cell pro-inflammatory cytokine production in AGS cells. Immunohistochemical staining of gastric tissue from Mongolian gerbils was used to confirm VacA-induced pro-inflammatory cytokine production and the effects of NaCl on this VacA-induced response.
RESULTS
Addition of VacA alone reduced AGS cell viability (P < 0.05), and this reduction was enhanced by high doses of NaCl (P < 0.05). VacA alone induced expression of TNF-alpha, IL-8 and IL-1beta, while NaCl alone induced expression of TNF-alpha and IL-1beta. Changes in mRNA levels in the presence of both VacA and NaCl were more complicated. For the case of TNF-alpha, expression was dose-dependent on NaCl. IL-6 mRNA was not detected. However, low levels of IL-6 were detected by ELISA. Positive immunohistochemical staining of IL-1, IL-6, and TNF-alpha was found in gastric tissue of H pylori-infected gerbils fed with either a normal diet or a high salt diet. However, the staining of these three cytokines was stronger in H pylori-infected animals fed with a 5 g/kg NaCl diet.
CONCLUSION
VacA decreases the viability of AGS cells, and this effect can be enhanced by NaCl. NaCl also affects the production of pro-inflammatory cytokines induced by VacA, suggesting that NaCl plays an important role in H pylori-induced gastric epithelial cell cytotoxicity.
目的
确定幽门螺杆菌（H pylori）空泡毒素（VacA）是否调节促炎细胞因子（IL-1β、IL-8、TNF-α和IL-6）的释放或改变胃上皮细胞活力，并确定氯化钠是否影响这些VacA诱导的变化。
方法
通过测量中性红摄入VacA处理的人胃上皮（AGS）细胞空泡中的量来确定空泡化活性。通过直接细胞计数评估AGS细胞活力。进行特异性酶联免疫吸附测定（ELISA）和逆转录聚合酶链反应（RT-PCR），以检查幽门螺杆菌VacA和氯化钠对AGS细胞中细胞促炎细胞因子产生的影响。使用蒙古沙鼠胃组织的免疫组织化学染色来确认VacA诱导的促炎细胞因子产生以及氯化钠对这种VacA诱导反应的影响。
结果
单独添加VacA会降低AGS细胞活力（P < 0.05），高剂量氯化钠会增强这种降低作用（P < 0.05）。单独的VacA诱导TNF-α、IL-8和IL-1β的表达，而单独的氯化钠诱导TNF-α和IL-1β的表达。同时存在VacA和氯化钠时mRNA水平的变化更为复杂。对于TNF-α，表达呈剂量依赖于氯化钠。未检测到IL-6 mRNA。然而，通过ELISA检测到低水平的IL-6。在喂食正常饮食或高盐饮食的幽门螺杆菌感染沙鼠的胃组织中发现IL-1、IL-6和TNF-α的免疫组织化学染色呈阳性。然而，在喂食5 g/kg氯化钠饮食的幽门螺杆菌感染动物中，这三种细胞因子的染色更强。
结论
VacA降低AGS细胞活力，氯化钠可增强这种作用。氯化钠还影响VacA诱导的促炎细胞因子的产生，表明氯化钠在幽门螺杆菌诱导的胃上皮细胞细胞毒性中起重要作用。
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