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目的观察硒对致癌剂氧化偶氮甲烷(AOM)所致大鼠结肠癌形成过程中,垂体远侧部ACTH阳性细胞的影响。方法随机将20只3周龄SPF级断乳雄性SD大鼠分为正常对照组、实验对照组、致癌剂前补硒组、致癌剂后补硒组。用AOM(15mg/kg)每周腹腔注射,连续2周,诱导大鼠结肠癌形成。亚硒酸钠(Na2SeO3)水溶液(4mg/L)分别在AOM前、后干预,并持续至实验结束。各组均于34周后取大鼠垂体,用免疫组织化学SP法,观察垂体远侧部ACTH阳性细胞的形态结构及免疫组织化学反应强度,并进行图像分析。结果亚甲基蓝染色光镜下观察,可见AOM腹腔注射的大鼠结肠黏膜出现异常隐窝(AC)和异常隐窝灶(ACF)。免疫组织化学法显示,实验对照组大鼠垂体远侧部ACTH阳性细胞与正常对照组比较,阳性反应显著性增强(P<0.01);硒干预的各组与实验对照组相比,ACTH阳性细胞的阳性反应进一步增强(P<0.01)。结论硒可增强AOM所致大鼠结肠癌形成过程中垂体远侧部ACTH阳性细胞的功能。
Objective To investigate the effect of selenium on ACTH positive cells in the distal part of pituitary during the carcinogenesis of oxidative stress agent azoxymethane (AOM) in colon cancer. Methods Twenty male Sprague-Dawley (SD) weaned Sprague-Dawley (SD) rats at 3 weeks of age were randomly divided into normal control group, experimental control group, pre-selenium group of carcinogen and selenium group of carcinogen. AOM (15mg / kg) was injected intraperitoneally weekly for 2 weeks to induce colon cancer in rats. Sodium selenite (Na2SeO3) aqueous solution (4mg / L) before and after the AOM intervention, and continued until the end of the experiment. After 34 weeks, the pituitary glands of rats in each group were taken. The morphology and structure of ACTH positive cells in the distal pituitary gland and the intensity of immunohistochemical reaction were observed by immunohistochemical SP method, and the images were analyzed. Results Methylene blue staining showed that there were abnormal crypts (ACs) and abnormal crypts (ACFs) in colonic mucosa of rats injected with AOM intraperitoneally. Immunohistochemistry showed that ACTH positive cells in the distal pituitary of the experimental control group were significantly increased compared with the normal control group (P <0.01). Compared with the experimental control group, ACTH positive cells Positive reaction was further enhanced (P <0.01). Conclusion Selenium can enhance the function of ACTH positive cells in the distal pituitary in AOM-induced colon cancer.