不同剂量辐射对NOD/SCID小鼠肠损伤的影响

摘要

目的 研究不同剂量辐射对NOD/SCID小鼠肠损伤的影响,寻找适合建立NOD/SCID小鼠放射性肠损伤模型的辐射剂量.方法 将40只雄性健康SPF级NOD/SCID小鼠随机分为空白对照组、4 Gy照射组、5 Gy照射组、6Gy照射组4组,每组10只.照射组小鼠全腹接受单次照射剂量分别为4、5、6Gy,剂量率为1 Gy/min.观察各组小鼠的一般情况、体质量变化、肠道细菌移位情况及病理学改变进行肠损伤的评估.结果 照射后15 d,4、5、6Gy照射组小鼠的生存率分别为60％、50％、30％;细菌移位率分别为20％、50％、70％;5 Gy照射组(P =0.015)和6 Gy照射组(P=0.011)小鼠的体质量明显低于空白对照组.4Gy照射组小肠绒毛长度变低;5Gy照射组肠黏膜绒毛结构宽大低平,并倒状,伴有上皮细胞脱落,腺体发生萎缩,隐窝结构破坏;6Gy照射组肠黏膜绒毛结构受损,绒毛离断破碎,隐窝结构缺失,组织间有大量炎症细胞浸润,可见点状出血或坏死.空白对照组、4Gy照射组、5Gy照射组、6Gy照射组小鼠的小肠绒毛长度分别为(361.77±22.77)、(291.68±32.45)、(248.03±51.09)、(195.90±26.39) μm,其中,4Gy照射组(P =0.005)、5Gy照射组(P＜0.001)、6 Gy照射组(P ＜0.001)均明显低于空白对照组;5Gy照射组(P =0.041)和6Gy照射组(P=0.001)明显低于4 Gy照射组;6Gy照射组明显低于5Gy照射组(P =0.020).结论 5Gy的腹部照射即可引起小鼠体质量减轻,肠黏膜绒毛表面坏死脱落,炎性细胞浸润,小鼠生存率和细菌移位率均稳定.%Objective To study the effect of different doses of radiation on intestinal injury,with an attempt to find the optimal radiation dose for establishing intestinal injury models in NOD/SCID mice.Methods Forty healthy male SPF-grade NOD/SCID mice were divided randomly into four groups:blank control group and 4-,5-,6-Gy irradiatio groups,with 10 mice in each group.The irradiation rate was 1 Gy/min.The general conditions,body weight,intestinal bacterial translocation,and histopathologic changes were observed and compared.Results The survival rate was 60％,50％,and30％ inthe4-,5-,and6-Gygroups15 days after irradiation,and the intestinal bacterial translocation rate was 20％,50％,and 70％,respectively.The body weights in 5-Gy group (P =0.015) and 6-Gy group (P =0.011) were significantly higher than that in blank control group.The length of small intestinal villi decreased in the 4-Gy group.In the 5-Gy group,the structure of intestinal mucosa villi became wide,flat,and inverted,along with the shedding of epithelial cells,the atrophy of glands,and the damage of recess structures.In the 6-Gy group,the structure of intestinal mucosal villi was damaged,the villi were ruptured and smashed,and the recess structures were missing;meanwhile,there was a large amount of inflammatory cell infiltration between tissues,along with visible spotty bleeding and necrosis.The length of small intestine villi in the blank control group and 4-,5-,and 6-Gy groups were (361.77 ±22.77),(291.68 ± 32.45),(248.03 ± 51.09),and (195.90 ± 26.39) μm,respectively.In particular,it was significantly shorter in 4-Gy group (P =0.005),5-Gy group (P ＜ 0.001),and 6-Gy (P ＜ 0.001) than in the blank control group,was significantly shorter in the 5-Gy group (P =0.041) and 6-Gy group (P =0.001)than in the 4-Gy group,and significantly shorter in 6-Gy group than in the 5-Gy group (P =0.020).Conclusion 5-Gy irradiation in mice models can decrease body weight,cause the damage of intestinal mucosa and the shedding of inflammatory cells,with stable survival rate and bacterial translocation rate.