目的　研究N - -甲基亚硝基脲 (MNU)诱发大白鼠膀胱肿瘤的作用。方法　以MNU为诱癌剂 ,进行大白鼠膀胱灌注 ,以光镜、扫描电镜、透射电镜等为观察手段 ,对其诱发的膀胱肿瘤进行观察。结果　每次灌注MNU2mg 只 ,每 2周 1次 ,共 4次 ,8周诱发膀胱肿瘤率 10 0 % ,其组织学形态及病理特征与人膀胱肿瘤十分相似。结论　MNU诱发的大白鼠膀胱肿瘤为一理想的动物模型。 Objective To study the effect of N-methyl nitrosoureas (MNU) on bladder tumors in rats. Methods MNU was used as a carcinogen to instill bladder in rats. Light microscope, scanning electron microscope and transmission electron microscope were used as observation methods to observe the bladder tumors induced by them. Results Each time MNU2mg was infused only once every 2 weeks for 4 times, and the rate of bladder tumor induced by 8 weeks was 100%. The histological morphology and pathological features were very similar to human bladder tumors. Conclusion MNU-induced bladder tumors in mice are an ideal animal model.