【作者】 刘艳娟；

【导师】 王小龙；

【作者基本信息】 南京农业大学 ， 临床兽医学， 2005， 硕士

【摘要】 硒是人和动物必需的微量元素,具有提高机体免疫力、抗自由基、延缓衰老、颉抗有毒元素、抗癌及防止某些地方性流行病等多种功能。我国70%的地区存在着不同程度的硒缺乏。同时,近年来流行病学调查和干预实验均提示,硒的缺乏与人类肿瘤的发生相关。因此,硒在肿瘤发生中的作用业已成为国内外又一个研究热点。 本实验以二乙基亚硝胺诱发大鼠肝癌为模型,观察不同浓度富硒麦芽对大鼠肝癌发生、发展的影响;着重应用免疫组化方法观察增殖细胞核抗原及肿瘤血管生成等方面的变化,以探讨富硒麦芽的抗癌机理。 实验Ⅰ 富硒麦芽对二乙基亚硝胺诱发大鼠肝癌发生过程的抑制作用 本实验观察富硒麦芽在化学致癌剂二乙基亚硝胺（diethylnitrosamine,DEN）诱发大鼠肝癌过程中,对肝癌发生、发展的影响。体重120～150g清洁级SD雄性大鼠185只随机分为5组:Ⅰ组为正常对照组,25只:Ⅱ组为模型对照组,40只,分别在日粮中添加亚硒酸钠至硒含量为0.1 mg·kg^-1;Ⅲ-Ⅴ组为富硒麦芽组,每组40只,日粮中添加富硒麦芽使硒含量分别达0.3、1.0、3.0 mg·kg^-1;各组麦芽含量与Ⅴ组一致,不足部分以普通麦芽粉补足。各组日粮营养成分接近,均达美国NRC标准。Ⅱ-Ⅴ组以100 mg·L^-1的DEN溶液连续喂饮诱癌16周,然后改饮常水至18周末。动态观察各组大鼠的体重、病理形态学、丙氨酸氨基转移酶（alanine amiotransterase,ALT）、碱性磷酸酶（alkaline phosphatase,ALP）、白蛋白（albumin,ALB）的变化;18周末,处死各组所有大鼠,记录眼观可见的肝表面癌结节数、体重以及肝重,并计算肝/体重比和肝癌发生率。结果显示,富硒麦芽组大鼠病理形态学变化较模型对照组轻,肝表面癌结节数、肝/体重比、肝癌发生率、血浆ALT、ALP活性低于或显著低于模型对照组,血浆ALB含量高于或显著高于模型对照组。表明补充一定量的富硒麦芽能减轻DEN所致的肝损伤,延缓和阻滞大鼠肝癌的发生、发展进程,而且呈现一定的剂量-效应关系。 实验Ⅱ 富硒麦芽对DEN诱发大鼠肝癌增殖细胞核抗原的抑制作用 本实验观察富硒麦芽对DEN诱发大鼠肝癌增殖细胞核抗原的抑制作用。实验动物分组同实验Ⅰ。在诱癌开始的第4、8、12、16及18周每组随机选取5只大鼠断头处死,利用免疫组织更多还原

【Abstract】 Selenium is an essential trace element to animal and human nutrition. Its functions include improving immunity, resisting free radicals, postponing aging, detoxification from some poisionous elements, repressing cancers, and avoiding some regional epidemics etc. Selenium deficiency or potential deficiency is very common with certain extent in the world. In China, about 70% of the territory is short of Se with different extent. In recent years, epidemiological research and interferential experiment indicate that Se deficiency shows positive correlation with tumor occurrence. Therefore, effect and mechanism study of Se on tumor has become an international hotspot investigation.In this experiment, Se-enriched malt was used as selenium sources, and its effect on the progress of hepatocarcinogenesis induced by diethylnitrosamine in rats was studied and its immunohistochemistry study on Proliferating cell nuclear antigen (PCNA) and microvessel density were especially investigated.Test I Effect of selenium-enriched malt on the hepatocarcinogenesis induced by diethylnitrosamine in rats. The effect of selenium-enriched malt on the process of experimental hepatocarcinogenesis induced by diethylnitrosamine (DEN) in rats were observed. One hundred and eighty-five healthy male SD rats weighted 120~150g were randomly divided into five groups. Twenty-five rats in group I were fed with diet containing 0.1 mg·kg~-1 selenium as sodium selenium, designed as normal control; forty rats in group II were fed with diet containing 0.1 mg·kg~-1 selenium as sodium selenium, designed as model control; group III-V with forty rats each were fed with diet containing 0.3, 1.0, 3.0 mg·kg~-1 selenium as selenium-enriched malt respectively. To balance the nutrition content among each group, normal malt which was not treated with selenium was added into the diets of the relative groups. The nutrition contents except the selenium content of the diet in each group were similar and accord with the standard of NCR.Drinking water with 100 mg·L~-1 diethylnitrosamine (DEN) were given to rats in group II -V for sixteen weeks to induce the heptocarinoma, after then normal water was given in another two more weeks. During the course of hepatocarcinogenesis, body weight, histopathological changes of liver, and alanine amiotransterase (ALT), alkaline phosphatase (ALP) and albumin (ALB) in plasma were observed. At the end of the eighteenth week, all the remainder rats were killed humanely and the number of hepatoma nodules, body weight, liver weight, relative liver weight and hepatoma incidence were recorded. The results indicated that histopathological changes of liver, the number ot hepatoma nodules, relative liver weight, hepatoma incidence and activities of plasma ALT, ALP activies in the groups of selenium-enriched malt were lower or significantly lower than those in the model group, while plasma ALB was higher or significantly higher than those in the model group, and the relationship of dosage-effect were also showed with certain extent in this experiment. The result demonstrated that selenium-enriched malt could attenuate the lesion of liver cells induced by DEN and postpone the progress of hepatocarcinogenesis in rats.Test 2 Effect of selenium-enriched malt on Proliferating cell nuclear antigen in the hepatoma induced by diethylnitrosamine in rats. The aim of this experiment was to observe the effect of selenium-enriched malt on Proliferating cell nuclear antigen (PCNA) in the hepatoma induced by diethylnitrosamine in rats. The treatments to the rats were same as the experiment I. At the end of forth, eighth, twelveth, sixteenth and eighteenth week, five rats of each group were selected randomly and killed humanecly, and the expression of PCNA of liver was examined by immunohistochemistry. The number of the positive PCNA cells was counted, and then the PCNA index (PI) at the end of eighteenth week was also caculated. The results indicated that the number of PCNA positive cells in high content selenium-enriched malt groups were significantly lower than th更多还原