AOM所致大鼠结肠癌形成过程中脑垂体远侧部TSH阳性细胞免疫组织化学观察

Observation of immunohistochemistry on the TSH positive cells in the pars distalis of pituitary of rat with colon cancer induced by azoxymethane

目的:观察氧化偶氮甲烷(azoxymethane,AOM)所致大鼠结肠癌形成过程中,大鼠脑垂体远侧部促甲状腺激素(thyroid stimulating hormone,TSH)细胞的免疫组织化学变化并初探其意义。方法:用断乳SD(Sprague Dawley)雄性大鼠30只,分为AOM实验组和对照组。实验组用AOM(15 mg/kg)每周腹腔注射,连续2周,诱导大鼠结肠癌的形成。分别于实验第10,30,34周取材,用免疫组织化学、图像分析法观察大鼠实验性结肠癌形成过程中,脑垂体远侧部TSH阳性细胞的变化。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(aberrantcrypt,AC)和异常隐窝灶(aberrant crypt foci,ACF)。免疫组织化学显示,与同期正常对照组相比,实验组大鼠垂体远侧部TSH阳性细胞阳性反应显著性减弱(P<0.05)。结论:在大鼠实验性结肠癌形成过程中,脑垂体远侧部TSH细胞变化可能与机体肿瘤的发生有关。

Objective： To observe the TSH positive cells in the pars distalis of pituitary of rat with colon mucosa cancer induced by azoxymethane （AOM） by immunohistochemical staining. Methods： Thirty threeweek old Sprague Dawley（ SD）male rats were randomly divided into two groups： Normal control group and experimental group. To induce rat colon mucosa cancer, 3-week old SD male rats （ experimental group） received intraperitoneal injections of AOM at a dose of 15 mg/kg once a week for two weeks. The rat pituitary tissues were excised from the 10-week, the 30-week and the 34-week old rats. To observe the morphological changes of the TSH positive cells in the pars distalis of pituitary using immunohistochemical methods, the results were analyzed by image analysis system. Results： Stained by methylene blue, ACF and AC were showed in colon mucosa of rats received two weekly intraperitoneal injections of AOM. With immunohistochemical methods, the TSH positive cells in the experimental group displayed significant decrease compared with the homeochronous normal control group （ P 〈 0.01 ）. Conclusion： The results suggested that the TSH positive cells in the pars distalis of pituitary of rat with colon mucosa cancer induced by AOM might be related with the tumorigenesis.