Abstract: Objective To observe the spontaneous lesions of SD Rats of different week-old, sexs,and feeding environments,and to provide the background database for pathological evaluation in drug safety study. Method SPF SD rats of normal control groups in drug safety tests，male and female included，separately kept under the center barrier and the ordinary environment，were killed at respectively 19，23，32 and 36 weeks time points．Tissues were examined under optical microscope，as well as animal disease type and disease incidence were counted．Result Compared with barrier environment，the incidence of spontaneous lesions of respiratory system was markedly increased in SD rats under ordinary environment．In addition，the incidence of spontaneous lesions of SD rat trended to increase with age in both feeding environments．Meanwhile，there were obvious sex differences in a few lesions，especially in progressive cardiomyopathy and mineralization in kidney．Spontaneous lesions consisted of progressive cardiomyopathy，focal inflammatory cell infiltrate (granulomatous inflammation included) in liver，spontaneous altered hepatocellular focus，vacuolation of the hepatic cell，focal inflammatory cell infiltrate in lung，aggregates of alveolar macrophages，mineralization in kidney，interstitial inflammatory cell infiltrate in kidney，atrophy in pancreas， inflammatory cell infiltrate in trachea，interstitial inflammation in prostate，atrophy of seminiferous tubules in testis，exfoliation of germ cell in testis，inflammation in endometrium and inflammation in vagina and so on．Conclusion The present study enriched the existing pathology background information of laboratory animal，and provided the reference for relevant technical personnels．

Key words: SD rat, spontaneous lesions, Pathology

摘要： 目的 观察不同环境下、不同周龄、不同性别SD大鼠的自发性病变发病情况，为药物安全性研究的病理学评价提供背景资料。方法 采用本中心安评试验中空白对照组SD大鼠，雌雄兼用，分别饲养于屏障系统和普通环境中，分别在19、23、32、36周龄等时间点处死解剖，常规制作病理切片，光学显微镜下观察主要组织器官的病理改变,统计动物自发性病变的类型和发病率。结果 与屏障系统相比较，普通环境大鼠呼吸系统的自发病变发生率明显升高；此外，在屏障环境和普通环境饲养条件下，SD大鼠自发病变发生率均随周龄增长而有增加的趋势；同时，少数病变均呈现较为明显的性别差异，其中以进行性心肌病和肾脏矿物质沉着最为明显。病理组织学检查可见进行性心肌病、肝脏灶性炎细胞浸润、肝细胞空泡变性、自发变异肝细胞灶、肺脏灶性炎细胞浸润、肺泡内泡沫细胞聚集、肾脏矿物质沉着、肾间质炎细胞浸润、胰腺萎缩、气管炎细胞浸润、前列腺间质炎症、睾丸曲细精管萎缩、曲细精管生精上皮细胞脱落、子宫内膜炎症和阴道炎症等主要自发性病变。结论 本文报告的SPF级SD大鼠的各种自发性病变的种类及其发生率丰富了实验动物的背景数据资料，可为相关技术人员提供参考。

关键词: SD大鼠, 自发病变, 病理学