4种富硒植物预防MNNG诱发大鼠胃癌效果研究 二、不同源硒预防大鼠胃癌的安全性对比研究

目的对比研究长期摄入高剂量不同源硒的安全性。方法以亚硒酸钠为对照硒材料,采用N-甲基-N′-硝基-N-亚硝基胍(MNNG)诱发大鼠胃癌模型,连续灌以4种不同富硒植物(高剂量硒)17周,测定肝脏谷胱甘肽硫转移酶(GST)、血清谷草转氨酶(AST)和血清谷丙转氨酶(ALT)活性,并观察肝脏和肾脏的病理变化。结果各组大鼠肝GST活性均无显著性差异;75μg/kg bw(以Se计,下同)亚硒酸钠低剂量组大鼠血清AST和ALT活性不仅显著高于空白对照和MNNG组,而且显著高于150μg/kg bw和300μg/kg bw植物硒处理组(P<0.05)。病理分析发现75μg/kg bw亚硒酸钠低剂量组胆管周围有棕黄色颗粒,窦内枯否氏细胞轻度肥大、增生;其余各组未发现有意义的病变。结论亚硒酸钠毒性至少是实验用其它富硒植物的4倍。

JAM-1、E-cadherin及β-catenin在大鼠胃癌组织的表达

目的研究鼠胃癌组织粘附分子JAM-1,E-cadherin及β-catenin的表达情况,探讨胃癌的转移机制。方法诱发大鼠胃癌模型,用免疫组化及免疫印迹方法检测大鼠不同病理分期胃癌组织中JAM-1、Ecadherin及β-catenin的表达。结果 JAM-1表达水平随着胃癌的进展而下降,在癌细胞、血管和淋巴管表达的面密度随着胃癌的进展而下降。E-cadherin和β-catenin在胃癌细胞的阳性表达率随着胃癌的发生、进展而下降,E-cadherin表达于正常胃及胃癌组织的血管,β-catenin阳性表达于淋巴管而未见血管。结论 JAM-1,E-cadherin,β-catenin在胃癌组织表达水平随着胃癌的进展而下降,可能参与癌转移机制。

Gastric cancer induced by N-methyl-N'-nitro-N-nitrosoguanidine in rat with ulcers and expressions of ras and c-erbB2 genes

Objective: To observe the series of pathological changes during the development of gastric adenocarcinoma in ulcerative rats induced by N-methyl-N′-nitro-N-nitrosoguanidine (MNNG), and the expression profile of related oncogenic protein.Methods: MNNG was administered in rats with ulcers due to acetic acid treatment to induce gastric cancer, and the protein expressions of ras and c-erbB2 genes in the ulcer were examined immunohistochemically along with pathological examination.Results: The incidence of gastric adenocarcinoma in the model group reaches 40% (6/15), while none of the rats developed cancer in the control group with ulcers.Positive expressions of the proteins of p21ras and c-erbB2 were observed in the tissues undergoing canceration in the 6 rats of model group, but were not observed in the 5 control rats; p53 protein expression, however, failed to be detected in both groups.Conclusion: A new animal model of gastric cancer has been established in rats with gastric ulcer after MNNG treatment, which may facilitate the pharmacological research of gastric cancer.