N-甲基亚硝基脲诱导大鼠膀胱癌模型的动态观察

目的探讨N-甲基亚硝基脲（MNU）诱发SD大鼠膀胱癌的模型构建及动态变化。方法采用MNU进行大鼠膀胱灌注2mg／次，每2周1次，共4次。分别观察实验第3、5、7、9、12和14周的膀胱黏膜改变。结果膀胱灌注3周出现不典型增生，5周上述改变明显，7周有原位癌改变，9周膀胱内可见明显癌性肿块，12—14周证实为膀胱乳头状癌或浸润性癌，9周的致癌率为100％（6／6），其组织学改变及病理学特征与人膀胱癌相似。结论MNU灌注诱导构建大鼠膀胱癌模型方法简便、可靠。致癌经历上皮增生、乳头状瘤形成和癌变过程，为比较理想的动物模型。

Observation on Dynamic Histopathological Changes in Bladder Tumor Model Induced by N-methyl-N-nitrosourea in Rats

Objective To establish the bladder tumor model induced by N-methyl-N-nitrosourea in rats and to observe the dynamic histopathological changes of the bladder mucosa. Methods A biweekly doses of 2 mg MNU each time for 8 weeks intravesicular administration were given. The changes of the bladder mucosa were pathologically examinated at 3rd, 5th, 7th, 9th, 12th and 14th week. Results Untypical hyperplasia could be observed after 3 weeks of administration, the carcinoma in situ occurred at 7 weeks, distinctive tumor was found at 9 weeks, bladder papilloma or invasive carcinoma was observed at 12-14 weeks. The rate of carcinogenicity was 100%（6/6） after 9 weeks. The histological changes and the pathologic characters were very similar with human bladder tumor. Conclusion The method to induce bladder tumor by intravesicular administration of MNU is convenient and reliable. The carcinogenic process includes epithelial hyperplasia, papilloma and carcinomatous changes. It is an ideal animal model.