人脐带间充质干细胞肌肉注射健康大鼠心肌组织微血管及胶原纤维的表达

Effects of human umbilical cord mesenchymal stem cells via intramuscular injection on the myocardial micrangium and collagen expression in normal rats

背景:目前关于肌肉注射脐带间充质干细胞能否引起心脏异位病理性血管形成及是否增加胶原纤维合成促进心肌纤维化尚不明确。目的:探讨肌肉注射人脐带间充质干细胞对健康Wistar大鼠心肌组织微血管及胶原纤维合成的影响。方法:健康雄性Wistar大鼠60只,随机分为正常组、培养液组、上清液组、低剂量组、中剂量组、高剂量组6组,每组10只;各组于饲养第2周分别在大鼠四肢肌肉内注射PBS(人脐带间充质干细胞悬浮液)、DMEM液(人脐带间充质干细胞培养液)、人脐带间充质干细胞培养的上清液、人脐带间充质干细胞0.25×105个、人脐带间充质干细胞1.0×105个和人脐带间充质干细胞4.0×105个。肌肉注射4周后再次注射1次,剂量和部位同上。于第2次肌肉注射后4周处死大鼠,取左心室肌制作病理切片,免疫组织化学法检测大鼠心肌微血管密度,Masson染色法检测心肌组织胶原纤维的表达。结果与结论:(1)实验期间大鼠反应灵敏,活动、饮食正常,尿便正常,体质量增长良好,毛发色泽正常,未出现懒动、姿势运动异常等改变,注射部位无脱毛、红肿、溃疡、硬结形成等,各组大鼠均未见死亡;(2)CD34染色显示各组心肌组织微血管均呈强阳性表达;(3)Masson染色显示各组心肌组织胶原纤维均呈阳性表达;(4)各组间微血管密度及胶原纤维表达差异无显著性意义(F=0.110和0.585,P>0.05);(5)结果表明,肌肉注射人脐带间充质干细胞及其培养上清液对健康大鼠心肌组织微血管及胶原纤维表达无明显影响。

BACKGROUND：To date, it is stil unclear whether the intramuscular injection of heterogeneous umbilical cord mesenchymal stem cel s （UC-MSC） can cause cardiac ectopic pathological angiogenesis as wel as increase col agen synthesis to promote myocardial fibrosis. OBJECTIVE：To explore the effects of intramuscular injection of human UC-MSCs on myocardial micrangium and col agen expression in normal Wistar rats. METHODS：After 2 weeks of feeding, 60 male SPF Wistar rats were randomly assigned to receive intramuscular injection of PBS （normal group）, DMEM （culture medium group）, human UC-MSCs supernatant （supernatant group）, 0.25×105, 1.0×105, 4.0×105 human UC-MSCs （low-, moderate-and high-dose groups）, respectively （n=10 per group）. Al the rats were subjected to second injection （same dose） at 4 weeks after first intramuscular injection. Then, the rats were kil ed under anesthesia at 4 weeks after second injection, to take heart tissues from the left ventricle for pathological observation, immunohistochemical examination and Masson staining. RESULTS AND CONCLUSION：No alteration of the response, activity, victualage, faeces, weight growth, and fur was found, and there was no death in rats during the experiment. Al the rats had no symptoms of molt, inflammation, skin ulcer, scleroma. Strong positive expression of CD34 for the micrangium in the myocardial tissue was observed, and positive expression of the col agen in the myocardial tissue observed by Masson staining. There were no significant differences in the microvessel density and col agen expression in the myocardium among the groups （F=0.110 and 0.585, P〉0.05）. To conclude, hUC-MSCs or its supernatant via intramuscular injection has no effect on the micrangium and col agen expression in normal rats.