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目的:建立国内用于药物临床前安全评价致癌性实验替代方法的C57-ras转基因小鼠模型,并通过甲基亚硝基脲(Nmethyl-N-nitrosourea,MNU)进行初步验证。方法:C57-ras转基因雄性小鼠与BALB/c雌性小鼠杂交,子代通过PCR进行基因型检测,获得C57-ras转基因和野生型小鼠。实验设定2个剂量,75 mg·kg-1MNU和150 mg·kg-1MNU单次腹腔注射给药,共5个组,其中75 mg·kg-1MNU设3个组:(1)转基因小鼠MNU组;(2)野生型小鼠溶媒组;(3)野生型小鼠MNU组;150 mg·kg-1MNU设2个组:(1)转基因小鼠MNU组;(2)野生型小鼠MNU组。其中溶媒组给予同等体积柠檬酸缓冲液,给药后观察29周,观察动物一般症状、生存率、肿物出现时间及大体剖检观察并进行组织病理学检查。结果:75 mg·kg-1MNU给药组小鼠生存率高于150 mg·kg-1MNU。75 mg·kg-1MNU给药后诱发C57-ras转基因小鼠发生淋巴瘤;150 mg·kg-1MNU给药后诱发C57-ras转基因小鼠发生淋巴瘤、肺脏腺瘤和直肠纤维肉瘤。野生型动物溶媒组和野生型动物MNU组均无肿瘤发生。结论:初步验证了自主建立的C57-ras转基因小鼠模型,该模型是临床前药物安全性评价致癌性实验快速替代实验候选模型之一。
OBJECTIVE: To establish a C57-ras transgenic mouse model for the preclinical safety evaluation of carcinogens in drug pre-clinical trials in China and to conduct preliminary validation with Nmethyl-N-nitrosourea (MNU). METHODS: C57-ras transgenic male mice were crossed with BALB / c female mice and the offspring were genotyped by PCR to obtain C57-ras transgenic and wild-type mice. The experiment set two doses, 75mg · kg-1MNU and 150mg · kg-1MNU single intraperitoneal injection, a total of 5 groups, 75mg · kg-1MNU set up three groups: (1) transgenic mice MNU group; (2) wild-type mouse vehicle group; (3) wild-type mouse MNU group; 150 mg · kg-1 MNU two groups: (1) transgenic mouse MNU group; MNU group. The same volume of citrate buffer was given to the vehicle group. After the administration for 29 weeks, the animals were observed for their general symptoms, survival rate, tumor appearance time, gross necropsy and histopathological examination. Results: The survival rate of mice in 75 mg · kg -1 MNU group was higher than 150 mg · kg -1 MNU. Lymphoma was induced in C57-ras transgenic mice after administration of 75 mg · kg -1 MNU, and lymphoma, lung adenoma and rectal fibrosarcoma were induced in C57-ras transgenic mice after administration of 150 mg · kg -1 MNU. No tumorigenesis occurred in the wild-type animal vehicle group and in the wild-type MNU group. CONCLUSION: The autologous C57-ras transgenic mouse model was preliminarily validated. This model is one of the candidate rapid replacement experiments for preclinical drug safety evaluation of carcinogenicity.