幽门螺杆菌对胃上皮细胞Cox-2表达与凋亡的影响

Cydooxygenase-2 expression in gastric mucosal cells with H pylori infection and its relationship with apoptosis

目的:研究Cox-2在胃癌细胞中及胃黏膜组织中表达的意义,探讨其表达与胃上皮细胞凋亡的关系. 方法:将粗制H pylori总蛋白与胃上皮细胞株MKN28, AGS共同孵育,用RT-PCR及免疫组化染色法测定孵育前后细胞Cox-2表达的情况,同时检测了40例患者胃镜活检胃黏膜病变标本的Cox-2蛋白的表达及H pylori感染情况.用流式细胞术观察H pylori、选择性Cox-2抑制剂NS-398及二者共同诱导细胞凋亡的情况. 结果:与H pylori孵育后的MKN28细胞株中Cox-2表达增加;Cox-2蛋白在与H pylori共同孵育前后的MKN28细胞株中表达强度分别为0.26和0.40(P<0.05),AGS细胞中为0.29和0.31(P>0.05);Cox-2在胃癌中的表达明显高于浅表性胃炎(CSG)、萎缩性胃炎(CAG)组(P<0.05).流式显示,与H pylori孵育24,48 h MKN28细胞凋亡率分别为1.0%和5.7%(P<0.01);与10,100,200 μmol/L NS- 398孵育24 h及48 h的MKN28细胞凋亡率分别为1.2%, 14.0%,27.5%及1.5%,31.2%,51.8%,具有浓度、时间依赖性(P<0.01).与H pylori,NS-398共同孵育24, 48h的MKN28细胞凋亡率分别为12.2%,25.0%,其凋亡率低于单用NS-398(P<0.01). 结论:H pylori感染上调MKN28细胞中Cox-2的表达; Cox-2基因可抑制细胞凋亡,在胃癌发生发展过程中起重要作用,可能为胃癌形成的机制之一.

AIM: To investigate the expression of Cox-2 in MKN28 and AGS gastric cells and gastric mucosal lesions with H pylori infection, to determine whether Cox-2 gene expression by H pylori infection could influence gastric cell apoptosis and to identify the relationship between Cox-2 and gastric carcinoma. METHODS: The total H pylori proteins of various concentrations were incubated with MKN28 and AGS gastric cells in vitro. RT-PCR and S-P immunohistochemical staining were used to detect the expression of Cox-2 before and after the incubation. 40 patients who underwent endoscopy were detected with S-P method. Apoptosis induced by H pylori or selective Cox-2 inhibitor NS-398 or both was characterized by cell cycle kinetics with flow cytometry. RESULTS: Expression of Cox-2 in MKN28 gastric mucosal cells incubated with H pylori was significantly higher than that in non-incubated cells. Expression of Cox-2 protein in MKIM28 gastric cells before and after incubated with H pylori was 0.26 and 0.40 respectively (P<0.05), but in AGS gastric cells, the expression of Cox-2 protein was 0.29 and 0.31 before and after the incubation (P>0.05). Expression of Cox-2 protein in gastric carcinoma (GC) was higher than that in chronic superficial gastritis (CSG) and chronic atrophic gastritis (CAG) (P<0.05). The apoptosis rate when cells were incubated with H pylori for 24 h and 48 h was 1.0% and 5.7% (P <0.05). Apopto cells were also observed after treated with 10, 100, 200 μmol/L NS-398 for 24 h and 48 h, and apoptosis rate was 1.2%, 14.0% and 27.5%, and 1.5%, 31.4% and 51.8% respectively. However, the apopotosis induced by H pylori and NS-398 was lower than that induced by NS-398 alone (P<0.01). CONCLUSION: H pylori upregulates Cox-2 expression in MKN28 gastric mucosal cells In vitro. Cox-2 can inhibit the apoptosis, which may promote gastric carcingenesis.