MNNG加吐温20和维生素D_3对大鼠前胃的影响

Effect of vitamin D -3 on forestomach carcinogenesis induced by N methyl N' nitro N nitroso guanidine and tween 20 in rats

目的 研究胃癌发生、发展过程中，间质组织中血管反应与肿瘤的关系．方法 经水摄入Ｎ－ 甲基－ Ｎ１ － 基－ Ｎ － 亚硝基胍（ ＭＮＮＧ）和表面活性剂（ 吐温２０） 诱发大鼠肿瘤，饲料中添加维生素Ｄ３（ＶｉｔＤ３） 对肿瘤进行预防． 每８ ｗｋ 处死大鼠７ 只，３２ ｗｋ 实验结束．结果 ｗ ｋ １６ 实验组大鼠前胃鳞状上皮形态主要以血管密度增加、血管内皮细胞增生，３２ ｗｋ（ ＭＮＮＧ） ＋ 表面活性剂和ＶｉｔＤ３ 组肿瘤发生率高于ＭＮＮＧ 组（１０ ％ ） ，肿瘤发生率为６５ ％ ．结论 该组动物诱癌实验表明，肿瘤形成前主要以血管新生、血管ＥＣ 增生为主的病理性变化．

AIM To investigate the correlation between changes of microvessel and forestomach carcinogenesis in the rats. METHODS Forestomach carcinogenesis in rats was induced by topical administration of N methyl N' nitro N nitrosoguanidine(MNNG, 150*!mg ·L -1 ) and tween 20(0 4%) in drinking water. Four weeks later, rats were switched to the diet containing 1, 25 dihydroxyvitamin D 3[1,25(OH)2D3,2 5 and 5 0*!mg ·kg -1 ]. Animals were killed at week 8, 16,24 and 32, respectively. RESULTS At week 16, rats given MNNG and tween 20 showed increase in microvessel density and proliferation of endothelial cells. At the end of the experiment, the incidence of forestomach carcinoma in rats receiving 1, 25 (OH)2D3 ( 5 0*!mg ·kg -1 ) was dramatically higher (65%) than that of rats receiving MNNG and tween 20 (10%). CONCLUSION The endothelial cell proliferation and increased microvessel density in mucosa of forestomach occurred at precancerous stage during chemical induced carcinogenesis.