γ射线全身照射小鼠肠组织损伤效应及对肠道微生物的影响研究

Intestinal tissue injury and gut microbiome changes in mice treated with whole body irradiation by gamma rays

目的探讨0.5 Gy 60Coγ射线照射对小鼠肠道组织损伤及肠道微生物菌群的影响。方法采用C57BL/6N小鼠,0.5 Gy 60Coγ射线全身照射,于照射后1、3、7和14 d取小鼠空肠组织固定及冻存,取小鼠全肠粪便冻存;通过苏木素-伊红染色观察照射后空肠病理损伤,ki67免疫组化染色检测空肠隐窝细胞增殖变化,原位末端标记法检测空肠隐窝细胞凋亡改变,放射免疫法检测小肠肿瘤坏死因子(TNF-α)、白细胞介素-1β(IL-1β)、IL-6和IL-10表达;通过宏基因组测序分析照射后小鼠肠道菌群改变,LEfSe分析法、ROC分析法进一步筛选差异显著菌种。结果0.5 Gy 60Coγ射线照射后1 d空肠隐窝增殖细胞显著减少(P<0.05),照射后1、3 d空肠隐窝凋亡细胞显著增多(P<0.01);照射后7、14 d TNF-α表达,照射后1、3、7、14 d IL-1β和照射后3、7、14 d IL-6表达均显著升高(P<0.05),照射后7、14 d IL-10表达水平显著降低(P<0.05)。0.5 Gy 60Coγ射线照射后,在门、属、种水平肠道菌群组成发生显著变化,鼠乳杆菌、约氏乳杆菌、另枝菌属-未分类种、Mucispirillum schaedleri差异最为显著、LDA评分较高。结论0.5 Gy 60Coγ射线全身照射导致小鼠肠组织损伤,改变小鼠肠道菌群组成。

Objective To investigate the effects of 0.5 Gy 60Coγ-ray irradiation on intestinal tissue injury and intestinal microflora in mice.Methods C57BL/6N mice were irradiated with 0.5 Gy 60Coγ-ray at 1 d,3 d,7 d and 14 d after irradiation.Jejunum tissues were fixed and frozen,and feces were frozen.Hematoxylin-eosin staining was used to observe the pathological injury to jejunum after irradiation,ki67 immunohistochemical staining was adopted to detect the proliferation of jejunum crypt cells,and TdT-mediated dUTP nick end labeling was employed to detect the apoptosis of jejunum crypt cells.The expressions of TNF-α,IL-1β,IL-6 and IL-10 cytokines in small intestines were detected via radioimmunoassay.The changes of intestinal flora in mice after irradiation were analyzed by metagenomic sequencing,and LEfSe analysis and ROC analysis were used to screen the bacteria with significant differences.Results After 0.5 Gy 60Coγ-ray irradiation,the proliferative cells of the jejunal crypt were significantly decreased at 1 d after irradiation(P<0.05),while the apoptotic cells were significantly increased at 1 and 3 d after irradiation(P<0.01).The expression of TNF-αat 7 and 14 d after irradiation,that of IL-1βat 1,3,7 and 14 d after irradiation and that of IL-6 at 3,7 and 14 d after irradiation were significantly increased(P<0.05),while the expression of IL-10 at 7 and 14 d after irradiation was significantly decreased(P<0.05).After 0.5 Gy 60Coγ-ray irradiation,intestinal flora composition changed significantly at phylum,genus and species levels,and Lactobacillus murinus,Lactobacillus johnsonii,Alistipes-unclassified,Mucispirillum schaedleri underwent the most significant changes and had higher LDA scores.Conclusion The whole body irradiation of 0.5 Gy 60Coγ-ray can cause intestinal tissue damage and change the composition of intestinal flora in mice.