硒对大鼠胃癌形成的作用及其与5-HT的关系

Effect of Selenium on the Gastric Carcinogenesis and its Relationship with 5-HT in Rat

目的 探讨硒对MNNG(N甲基 N 硝基 N亚硝胍)诱导Wistar大鼠胃癌形成的作用及其与5 羟 色胺(5 HT)的关系。方法 用MNNG(20mg·kg-1)给大鼠灌胃,以诱导大鼠胃癌模型形成。用HE染色、显 微镜观察和AB PAS反应方法比较硒在MNNG诱导Wistar大鼠胃癌形成过程中的作用,用免疫组织化学SP 法和显微图像分析胃粘膜5 HT细胞的变化。结果 饮水中补充2mg·L-1和4mg·L-1的亚硒酸钠可以加 重胃粘膜的糜烂、出血,促进胃粘膜的肠上皮化生;在MNNG诱癌过程中发生了浆膜下平滑肌瘤,且亚硒酸钠 可以增加平滑肌瘤的发生率(P<0.05)。5 HT内分泌细胞的面数密度(NA)实验各组之间无显著差异,但是 低硒组平均光密度(MOD)明显高于正常对照组(P<0.01)。结论 在MNNG所致胃癌形成过程中亚硒酸钠 并不能降低大鼠胃癌的发生,其机制可能与胃粘膜5 HT的分泌成正相关。

Objective To investigate the effect of selenium on the gastric carcinogenesis induced by N-methyl-N-nitro-N-nitrosoguanidine (MNNG) and its relationship with 5-hydroxytryptamine (5-HT) in Wistar rat. Methods The gastric cancer was induced by MNNG (20 mg·kg -1) gavage in Wistar rat. Histopathologic changes were showed by methods of HE staining and Alcian Blue periodic acid schiff reaction (AB-PAS). The changes of 5-HT expression in gastric mucosa were detected by SP immunohistochemical method and analyzed by micro-image analysis. Statistical analysis was taken by SPSS. Results Dietary Na 2SeO 3(2 mg·L -1,4 mg·L -1) aggravated the gastric erosion and hemorrhage, and promoted the intestinal metaplasia of gastric mucosa (P<0.05). Leiomyoma was found in the process of induced rats gastric carcinoma and dietary Na 2SeO 3(2 mg·L -1,4 mg·L -1) increased incidence rate of leiomyoma (P<0.05). The numerical density of area (NA) of 5-HT cells did not show significant difference between groups, but mean optical density (MOD) of 5-HT endocrine cells increased significantly in low selenium group than in normal control group (P<0.01). Conclusion The dietary Na 2SeO 3 by piped drinking didnt decrease the incidence of gastric cancer induced by MNNG in Wistar rat, its mechanism might be related positively to the expression of 5-HT in gastric wall.