脐带间充质干细胞移植治疗大鼠急性肝功能衰竭以及移植途径的选择

r Therapeutic effects and pathways of human umbilical cord mesenchymal stem cells transplantation for rat acute liver failure model

目的探讨脐带间充质干细胞（hUCMSC）移植治疗大鼠急性肝功能衰竭的效果，并探讨移植途径。方法采用组织块贴壁法收集和培养hUCMSC，应用流式细胞术鉴定细胞。采用随机数字表法将SD大鼠随机分为经尾静脉移植组、经肝叶移植组、模型对照组及MSC对照组。采甩腹腔注射CCL4橄榄油（1：1）混合溶液2．5ml／kg建立大鼠急性肝功能衰竭模型。建模24h后，两移植组大鼠分别经尾静脉和肝叶输注hUCMSC悬液，未建模的MSC对照组大鼠经尾静脉输注hUCMSC悬液，建模的模型对照组大鼠经尾静脉输注生理盐水；移植后0h（即建模后24h）、24h、48h、72h、96h和1周检测各组大鼠的肝功能指标；移植后3d、1周和2周取各组大鼠肝脏组织行病例观察，采用免疫组织化学法检测肝组织中人CK18蛋白的表达，采用Real-timePCR检测肝组织中人CK8、CK18和AFPmRNA的转录水平。结果两移植组大鼠血清胆红素总量（TBil）和丙氨酸转氨酶（ALT）水平较模型对照组有明显改善（P〈0．05）。病理观察显示，与模型对照组比较，两移植组大鼠的肝细胞再生程度明显提高，炎症细胞浸润明显减少，肝脏病理修复作用增强。移植后3d，经尾静脉移植组和经肝叶移植组大鼠肝组织中均可检出人CK18蛋白，表达CK18的细胞主要沿汇管区分布，之后逐渐向肝小叶中央迁移和扩散。建模后1周和2周时，经尾静脉移植组和经肝叶移植组肝组织中CK8、CK18和AFPmRNA的相对表达量与模型对照组相比，差异均有统计学意义（P〈0．05）。经尾静脉移植组和经肝叶移植组的肝功能、移植细胞分化程度的比较，差异均无统计学意义（P〉0．05）。结论hUCMSC移植能改善急性肝功能衰竭大鼠的肝功能，修复肝脏病理损伤。经尾静脉与经肝叶输注hUCMSC的疗效相似。

Objective To explore the therapeutic effectiveness and pathways of human umbilical cord mesenchymal stem cells （hUCMSCs） transplantation for acute hepatic failure in rats. Method hUCMSCs were isolated from umbilical cord with attachment culture method, and the surface antigens were tested by flow cytometry. Forty-eight male Sprague Dawley rats were randomly divided into four groups. The animal model of acute liver failure was induced by injecting intraperitoneally with 50% olive oil solution of carbon tetrachloride （2. 5 ml/kg）. The treatment groups were injected with hUCMSCs suspension separately through the tail vein or injected into the liver 24 h post-modeling. Blood serum and liver tissues were collected at several time points to analyze the improvement of liver function and histological repair. Real-time PCR was used to detect the expression of human CK8, CK18 and AFP mRNA in liver tissues. Immunohistochemistry was used to detect the expression of human CK18 in liver tissues. Result There were statistically significant differences among liver functions after transplantation （P〈0. 05）. hUCMSCs improved histological status through enhancing hepatocellular regeneration and reducing inflammatory ceils. Real-time PCR results showed that the expression of CKS, CK18 and AFP mRNA was obviously increased in the tail vein transplantation group and hepatic lobe injection transplantation group as compared with the model group （P〈0. 05）. Immunochemistry results revealed that transplanted hUCMSCs in animal liver could differentiate into functional hepatocyte-like cells that expressed human CK18 as hepatocyte-specific marker in the tailvein transplantation group and hepatic lobe injection transplantation group. No significant differences in histological repair and grade of differentiation were examined between the tail vein transplantation group and hepatic lobe injection transplantation group （P〈0. 05）. Conclusion hUCMSCs can prompt the repair of acute liver failure and enhance pathological repair. Transplanted cells in animal liver can differentiate into functional hepatocyte-like cells that expressing hepatocyte-specific markers. Transplantation of hUCMSCs via the tail vein or direct injection into the liver had the similar therapeutic effects.