Abstract: Abstract: Objective To observe the weight of viscera and organ coefficient，and occurrence of spontaneous tumor of survival and dead Wistar rats during 2 years experiment，and investigate their death cause． Method The gross anatomy and histopathological examination for the rats sacrificed at the end of the two-year experiment and the dying or dead rats during the experiment were carried out instantly． Their body weight and weight of their brain，heart， lung，liver，spleen，kidney，adrenal glands，thymus，ovary，uterus，testis，and epididymis were measured and organ coefficients were calculated，and occurrence of spontaneous tumor was recorded． Result There were significant differences in weight of body，brain，heart，lung，liver，spleen，kidney，adrenal glands and organ coefficients of brain and adrenal glands between female and male rats survived for 104 weeks． The gross anatomy and histopathological examination revealed that 80. 5% of rats died of dyscrasia and multiple organ failure ( MOF) resulted from tumor lesions，17. 1% of rats died of MOF resulted from non-tumor lesions，and 2. 4% of rats succumbed to MOF caused by other lesions． There was no significant difference in death cause between male and female rats． Conclusion The present study provided background information for carcinogenicity tests performed on Wistar rats，and the tumor lesions are the leading death cause of Wistar rats．

Key words: Wistar rats, organ weight and coefficient, tumor, death cause

摘要： 摘要: 目的喂养Wistar 大鼠二年，观察试验期内存活与死亡大鼠的脏器质量、脏器系数及自发性肿瘤发生情况， 并分析试验期内死亡动物的死亡原因。方法对试验期结束尚存活的动物、试验中濒死或死亡的动物，及时进行 大体解剖及组织病理学检查，称其脑、心脏、肺脏、肝脏、脾脏、肾脏、肾上腺、胸腺、卵巢、子宫、睾丸及附睾脏器质量 并计算脏器系数，观察是否有自发性肿瘤发生。结果试验观察104 周存活大鼠雌性与雄性间比较，体质量、脑、 心脏、肺脏、肝脏、脾、肾脏、肾上腺脏器质量及脑、肾上腺脏器系数差异显著。通过对试验期内死亡或濒死的动物 大体解剖及组织病理学检查， 80. 5%大鼠因肿瘤性病变导致恶液质、多脏器衰竭死亡， 17. 1% 大鼠因非瘤性病变致 多脏器衰竭死亡， 2. 4%大鼠因其他病变致脏器衰竭死亡，雌雄动物间死亡原因未见统计差异。结论本实验为 Wistar 品系大鼠致癌性试验提供了相关的背景资料，肿瘤性病变是Wistar 品系大鼠致死的主要原因。

关键词: Wistar 大鼠, 脏器质量及系数, 肿瘤, 死亡原因