骨髓间充质干细胞移植对放射性肠损伤大鼠的修复作用及对JAK/STAT通路的影响

Effect of bone marrow mesenchymal stem cells transplantation on repair of radiation-induced intestinal injury in rats and its influence on JAK/STAT pathway

目的观察骨髓间充质干细胞(BMSCs)移植对放射性肠损伤大鼠的修复作用,并探讨BMSCs修复放射性肠损伤的机制。方法对SPF级SD大鼠胫骨和股骨骨髓细胞进行分离,传代培养、鉴定得到BMSCs。从26只健康SD大鼠中随机选取6只作为空白对照组,余下大鼠构建放射性肠损伤模型,将建模成功的20只大鼠随机分为模型组、BMSCs组(尾静脉注射BMSCs悬液)各10只。分别在最后一次注射BMSCs后1、2、3周,取各组大鼠小肠组织备用。采用苏木精-伊红(HE)染色法观察小肠组织病理变化情况;采用实时荧光定量(q RT)-聚合酶链反应(PCR)对小肠组织酪氨酸激酶(JAK)和信号转导子和转录激活子(STAT)m RNA水平进行检测;采用免疫组化法检测小肠组织p-JAK和p-STAT蛋白水平。结果成功分离培养BMSCs;与空白对照组比较,模型组小肠绒毛紊乱,黏膜上皮细胞坏死增加,肠黏膜坏死溃疡严重,移植BMSCs后,大鼠各项病理变化均明显恢复;与空白对照组比较,模型组JAK和STAT m RNA水平显著上调(P<0.05),移植BMSCs后,JAK和STAT m RNA明显下调至正常水平(P<0.05);与空白对照组相比,模型组p-JAK和p-STAT蛋白水平均显著升高(P<0.05),BMSCs治疗后,p-JAK和p-STAT蛋白水平均明显下降(P<0.05)。结论 BMSCs移植能够修复放射性肠损伤,并影响JAK/STAT通路中关键因子的磷酸化水平,提示BMSCs移植可能通过影响JAK/STAT通路而实现对放射性肠损伤的修复作用。

Objective To investigate the effect of bone marrow mesenchymal stem cells （BMSCs） transplantation on the repair of radiation-induced intestinal injury in rats, and to determine the mechanism of BMSCs in the repair of radiation-induced intestinal injury. Methods The tibial and femoral bone marrow cells of SPF-class SD rats were iso- lated, and the BMSCs were subeuhured and identified. From 26 healthy SD rats, 6 were randomly included as the blank control group, and the remaining rats were used to establish the radiation-induced intestinal injury model. Twenty rats with successful modeling were randomly divided into the model group and BMSCs group （BMSCs suspension inject- ed through caudal vein）, n=10 each. At 1, 2 and 3 weeks after the last injection of BMSCs, the small intestinal tissues in each group were reserved. The pathological changes of small intestinal tissues were determined by hematoxylin-eosin （HE） staining. The mRNA levels of tyrosine kinase （JAK）, signal transducer and activator of transcription （STAT） in the small intestinal tissues were examined by qRT-PCR. Immunohistochemistry was used to measure the protein levels of p- JAK and p-STAT in the small intestinal tissues. Results BMSCs were isolated and cultured successfully. Compared with the blank control group, disorder of villus, increased necrosis of mueosal epithelial cells and severe necrosis of in- testinal mucosa were found in the model group, whereas all the pathological changes of rats were significantly recovered after BMSCs transplantation. Compared with the blank control group, the mRNA levels of JAK and STAT in the model group were significantly up-regulated （P〈0.05）. After BMSCs transplantation, the mRNA levels of JAK and STAT were significantly down-regulated to the normal levels （P〈0.05）. Compared with the blank control group, the protein levels of p-JAK and p-STAT in the model group significantly increased （P〈0.05）. After BMSCs treatment, the protein levels of p- JAK and p-STAT significantly decreased （P〈0.05）. Conclusion Transplantation of BMSCs can repair radiation-in- duced intestinal injury and affect the phosphorylation of key factors in JAK/STAT pathway, suggesting that BMSCs transplantation may repair the radiation-induced intestinal iniury by affecting JAK/STAT pathway.