连黛片抗大鼠胃癌及对p21ras、c-erbB2、Rb和p53蛋白表达的影响

The Inhibiting and Interfering Effects of Liandai Tablet(连黛片)on Gastric Cancer and Oncogene Expression in Rats

目的:观察连黛片抗胃癌作用及其机理。方法:以 N-甲基-N′-硝基-N-亚硝基胍(MNNG)诱发大鼠胃及十二指肠癌,连黛片灌胃给药,病检及免疫组化法观察药效。结果:连黛片组大鼠癌的发生率为5.6%,低于空白组的38.9%(P<0.05)。病理学计量分析显示,病理损伤程度连黛片组大鼠低于空白组(P<0.05)。空白组8只大鼠胃病变组织中发现p21ras5只和 c-erbB2 3只蛋白呈阳性表达,连黛片组7只大鼠上述蛋白表达均呈阴性。两组所有标本的 Rb 和 p53表达均呈阴性。结论:连黛片具有降低 MNNG诱发胃及十二指肠癌发生的作用,能减轻病理损伤,其作用机理似与抑制 ras 和 c-erbB2过表达有关,但对 Rb 缺失无保护作用,p53可能不是 MNNG 致大鼠胃癌的靶基因。

Objective:To observe the effect of Liandai Tablet(LDT,composed of Rhizoma Copitidis,Fructu Evodiae,Indigo Pulverata Levis,etc.) on preventing experimental gastric and duodenal cancer and interfering p21ras,c-erbB2,Rb,p53 oncogene expression.Methods:Administering N-methyl-N'-nitro-N-nitrosoguandidine(MNNG) to the drinking water for rats to induce gastric and duodenal cancers and then treating the rats with LDT for 3 months(gastrogavage,1.5g/ kg).The occurrence of carcinoma was observed by pathological examination and the expression of p21ras,c-erbB2,Rb, p53 in lesion tissues were examined by S-P or LSAB immunohistocbemical technique.Results:The incidence of gastric and duodenal carcinoma in LDT group was 5.6% (1/18),which was significantly lower than that of the control group (38.9%,7/18,P<0.05).The average score of pathological quantitive analysis in LDT group was also lower than that of the control group (P<0.05).Immunohistochemical examination found that in 8 rats of the control group,5 rats showed positive p21 ras expression and 3 showed positive c-erbB2 expression,while in all the 7 rats of the LDT group, the ahove two expressions were negative.Rb and p53 were negative in all rats of both groups.Conclusions:LDT has a preventive effect on gastric and duodenal cancer in rats,which might be related to the depression of p21ras and c-erbB2 oncogene expression,but it could not protect the deficit of Rb.Besides,p53 is not the target gene of MNNG-induced can- cer in rats.