C57BL/6小鼠急性放射性肠炎模型的建立

Establishment of Acute Radiation Enteritis Model in C57BL/6 Mice

目的 用不同剂量的X射线照射C57BL/6小鼠,以建立急性放射性肠炎小鼠模型,为进一步探索急性放射性肠炎的发生和作用机制奠定基础。方法 取SPF级雄性6-8周龄C57BL/6小鼠23只,随机分为对照组(n=3)和6、12、15和18Gy(n=5)不同剂量照射实验组,观察小鼠15d存活率和体重变化情况。另取60只小鼠,随机分为对照组和6Gy、12Gy、15Gy(n=15)不同剂量照射实验组,分别在第1、3、7d颈椎脱臼处死各5只小鼠,取末端回肠组织做病理切片,进行HE染色、Masson染色,采用RT-qPCR方法检测肠组织中促炎细胞因子IL-1β、IL-6、TNF-α和促纤维化生长因子TGF-β1的mRNA相对表达量变化。结果 辐照后第3d,照射组6Gy、12Gy、15Gy较对照组促炎细胞因子IL-1β、IL6、TNF-α和促纤维化生长因子TGF-β1有显著性变化,15Gy较对照组照射组小鼠回肠绒毛高度降低,隐窝数目减少、深度变浅,隐窝腔变大,肠纤维化更明显,而6Gy及12Gy相应表型不明显。结论 X射线一次性腹部照射,大体观察和病理切片表明15Gy和18Gy照射组具有临床急性放射性肠炎的症状,18Gy照射组小鼠会出现死亡,不能为进一步实验研究提供模型,15Gy可作为急性放射性肠炎小鼠模型的最佳照射剂量。

Objective To establish a mouse model of acute radiation enteritis by irradiation of C57BL/6 mice with different doses of X-ray,and to lay the foundation for further exploration of the occurrence and mechanism of acute radiation enteritis.Methods Twenty-three male C57BL/6 mice aged 6-8 weeks were randomly divided into the control group(n=3)and the experimental group(n=5)irradiated with different doses of 6,12,15 and 18Gy.The 15-day survival rate and body weight of the mice was observed.Another 60 mice were randomly divided into the control group and the experimental group with different doses of 6,12 and 15Gy(n=15)irradiation.On the 1st,3rd and 7th day,5 mice in each group were sacrificed for cervical dislocation.The relative changes of mRNA expression of pro-inflammatory cytokines IL-1β,IL-6,TNF-αand pro-fibrotic growth factor TGF-β1 in intestinal tissue were-detected by RT-qPCR.Results On the third day after irradiation,there were significant changes of pro-inflammatory cytokines IL-1β,IL6 and TNF-αin the irradiated group compared with the control group.The villus height of the ileum of the mice in the irradiated group of 6,12 and 15Gy was decreased,the depth and number of crypts of the mice in the irradiated group of 15Gy was decreased and the crypt cavity was enlarged.Intestinal fibrosis was more obvious in the 15Gy irradiation group.Conclusion one-time abdominal irradiation of X-ray,the gross observation and pathological section showed that the 15Gy and 18Gy irradiation groups had clinical symptoms of acute radiation enteritis,and the 18Gy irradiation group would cause death,which could not provide a model for further experimental study.15Gy could be used as the optimal dose for acute radiation enteritis mouse model.