BMSCs对溃疡性结肠炎合并肝损伤小鼠的肝脏修复作用及对紧密连接蛋白表达的影响

Effect of BMSCs on liver repair and expression of tight junction protein in mice with ulcerative colitis complicated with liver injury

目的探讨骨髓间充质干细胞(BMSCs)对溃疡性结肠炎(UC)合并肝损伤小鼠的肝脏修复作用,以及对肝脏紧密连接蛋白表达的影响。方法取4只3周龄Balb/c雄性小鼠,分离股骨以制备BMSCs。将15只6~7周龄Balb/c雌性小鼠随机分为阴性对照组、实验对照组及实验组,各5只。给予阴性对照组小鼠正常饮水,给予实验对照组及实验组小鼠饮用4%葡聚糖硫酸钠水溶液以建立UC模型,期间观察小鼠的一般表现。建模结束后,给予实验组小鼠注射BMSCs进行干预,阴性对照组及实验对照组小鼠则注射不含BMSCs的PBS。在干预后第9天处死小鼠,通过全自动生化仪检测小鼠血清肝功能指标,收集小鼠肝脏和结肠标本观察组织病理变化,并检测肝脏组织claudin-1、claudin-2、claudin-3、claudin-7、封闭蛋白及闭锁小带蛋白1(ZO-1)的mRNA表达情况。结果(1)实验对照组小鼠在建模过程中体重下降,大便呈糊状或水状,逐渐出现血便或便血,组织病理学检查提示结肠结构破坏明显及大量炎症细胞浸润;与实验对照组相比,实验组小鼠的UC症状及结肠病理表现均有所减轻。(2)实验对照组小鼠肝小叶结构紊乱、炎症细胞浸润,血清ALT、AST、碱性磷酸酶及总胆红素水平均较阴性对照组升高(均P<0.05),肝脏组织中claudin-1、claudin-3、claudin-7及ZO-1的mRNA表达水平均较阴性对照组降低(均P<0.05)。与实验对照组相比,实验组小鼠的肝功能及肝脏病理损伤均改善,且肝脏组织中claudin-1、claudin-3、claudin-7及ZO-1 mRNA表达水平均升高(均P<0.05)。结论BMSCs对UC合并肝损伤小鼠模型的肝脏有一定的修复作用,并可提高肝脏紧密连接蛋白mRNA的表达水平,其可能通过影响紧密连接蛋白的表达实现对肝脏的修复作用。

Objective To explore the effect of bone marrow mesenchymal stem cells(BMSCs)on liver repair and expression of tight junction protein in mice with ulcerative colitis(UC)complicated with liver injury.Methods A total of 4 Balb/c male mice with age of 3 weeks were obtained,and their femora were isolated for BMSCs preparation.A total of 15 Balb/c mice with age of 6-7 weeks were randomly assigned to negative control group,experimental control group or experimental group,with 5 mice in each group.The mice in the negative control group drank water normally,and the mice in the experimental control and experimental groups drank 4%dextran sodium sulfate solution to establish UC model.The general manifestation of the mice was observed during the period.After modeling,the injection of BMSCs was given to the mice in the experimental group for intervention,and the injection of PBS without BMSCs was given to the mice in the negative control and experimental control groups.The mice were killed on the 9day after intervention.The serum liver function indices of mice were detected by automatic biochemical analyzer.The liver and colon samples were collected for the observation of histopathological changes.The mRNA expressions of claudin-1,claudin-2,claudin-3,claudin-7,occludin and zonula occludens 1(ZO-1)in liver tissue were detected.Results(1)The mice in the experimental control group exhibited weight loss,pasty or watery feces,and suffered from bloody excrement or hemafecia during the modeling process.The histopathological examination implied that colon structure of the mice in the experimental control group was obviously destructed,and a large number of inflammatory cells infiltration occurred.Compared with the experimental control group,the UC symptom and pathological manifestations of colon were alleviated in the mice of the experimental group.(2)In mice of the experimental control group,the structure of liver lobules was disordered and inflammatory cells were infiltrated.The serum levels of ALT,AST,alkaline phosphatase and total bilirubin in the experimental control group were higher than those in the negative control group(all P<0.05),and the mRNA expressions of claudin-1,claudin-3,claudin-7 and ZO-1 in liver tissues were lower in the experimental control group than in the negative control group(all P<0.05).Compared with the experimental control group,the liver function and liver pathological injury of mice in the experimental group were ameliorated,and the mRNA expressions of claudin-1,claudin-3,claudin-7 and ZO-1 were elevated(all P<0.05).Conclusion BMSCs exert a certain repair effect on liver of the mice model of UC complicated with liver injury,and elevate the mRNA expression of liver tight junction protein,which may achieve effect of liver repair by affecting the expression of tight junction protein.