硒对MNNG诱导大鼠胃癌形成过程中肾上腺皮质酶活性的影响

EFFECTS OF SELENIUM ON CARCINOGENESIS AND ADRENAL CORTEX OF RAT STOMACH

目的观察硒在抗肿瘤发生过程中对大鼠肾上腺皮质3β-羟基类固醇脱氢酶(3β-HSD)、琥珀酸脱氢酶(SDH)和脂类的影响。方法给断乳1周的雄性Wistar大鼠以N甲基-N′-硝基-N亚硝基胍(MNNG)20mg/kg灌胃,每天1次,连续10d,以诱导大鼠胃黏膜异倍体形成(大鼠胃癌模型)。在灌胃前和灌胃后以普通饲料、低硒和高硒饲料等分别喂养。第25周时,用流式细胞仪测定硒对大鼠胃幽门黏膜异倍体形成的影响;同时用组织化学方法观察硒(0.2mg/kg及2.0mg/kg)在预防大鼠胃黏膜异倍体形成过程中,大鼠肾上腺皮质细胞中脂类以及SDH和3β-HSD的组织化学变化。结果1.硒能抑制大鼠胃黏膜异倍体形成;2.实验对照组与正常对照组相比,大鼠肾上腺皮质细胞3β-HSD和SDH组织化学反应明显增强(P<0.01),而肾上腺皮质细胞的脂滴含量明显减少(P<0.01);3.加硒实验各组与实验对照组相比,大鼠肾上腺皮质3β-HSD和SDH组织化学反应均减弱,尤以给MNNG前喂饲高硒饲料组减弱更明显,具有显著性差异(P<0.05);而肾上腺皮质细胞的脂滴含量均增多;尤以给MNNG前喂饲高硒饲料组增多更明显,与实验对照组相比具有显著性差异(P<0.05)。结论硒能抑制大鼠胃黏膜异倍体形成;MNNG所致大鼠胃黏膜细胞异倍体的形成和发展过程中其肾上腺皮质细胞功能发生明显变化;硒在预防大鼠胃黏膜异倍体形成过程中对大鼠肾上腺皮质细胞的功能也有一定的影响。

Objective To investigate the histochemical changes of 3β-hydroxysteroid dyhydrogenase（3β-HSD）, sucinic dehydrogenase（SDH） and lipid on rat adrenal cortex in the carcinogenesis-resistance with selentum. Methods Wistar rats stomach carcinogenesis （formation of aneuploid cells in the glandular stomach mucosa） was induced by MNNG（ N-methyl-N- nitroso-guanidine ,20 mg/kg）gavage. The changes of the adrenal cortex were studied by histochemistry and image analysis during preventing glandular stomach cancer with selenium（0.1 mg/kg and 2.0 mg/kg） Results 1. Dietary Se inhibited the aneuploid cell formation, which induced by MNNG gavage in Wistar rat stomach; 2. The histochemical reactions of 3β-HSD and SDH were both significantly stronger in experimental group than that in normal control group in the course of the rat stomach carcinogenesis（ P 〈 0.01 ） ; and the lipid significantly decreased in experimental control group than that in normal control group（ P 〈 0.01 ） ;3. The histochemical reactions of SDH and 3β-HSD were significantly weaker in Se dietary groups than that in experimental control group （ P 〈 0.05 ） ; and the lipid significantly increased in Se dietary groups than that in experimental control group （ P 〈 0.05 ）. Conclusion Dietary Se can inhibit the aneuploid cell formation, which induced by MNNG gavage in Wistar rat stomach. Adrenal cortex cells＇ s function changes when aneuploid cell formed and developed. Dietary Se can affect the function of endocrine cell in the process of rat stomach carcinogenesis.