摘要目的 观察早期注射骨髓间充质干细胞(BMSCs)对制动大鼠骨骼肌细胞Bcl-2、Bax蛋白表达的影响.方法 取幼龄大鼠(80～100 g)胫骨和股骨,分离培养大鼠BMSCs.用可塑性石膏制备有下肢管型固定肌萎缩模型,根据随机数字表法将24只大鼠分成假手术组、干细胞组、磷酸缓冲液(PBS)组,干细胞组大鼠下肢制动48 h后于比目鱼肌局部多点注射1×106个BMSCs;PBS组大鼠下肢制动48 h后注射等量PBS;假手术组大鼠下肢包裹相同重量石膏且不限制关节活动,48 h后注射等量PBS,14d后各组大鼠拆除石膏取标本分析.结果 培养中的大鼠BMSCs以梭形细胞为主,呈放射状排列的细胞集落,细胞生长旺盛,可连续稳定传代10代以上.实验中第4代BMSCs表面标志CD44 、CD90均呈阳性表达,阳性率分别为95.84％ 、96.00％,而CD34、CD45阳性率极低.与假手术组大鼠比目鱼肌中Bax和Bcl-2蛋白表达量[(0.14±0.1 1)、(0.81±0.06)]比较,干细胞组和PBS组Bax蛋白表达量[(0.41±0.08)、(0.63±0.10)]明显升高,两组Bcl-2蛋白表达量[(0.47±0.14)、(0.22±0.13)]明显降低;干细胞组中Bax蛋白的表达水平较PBS组低,Bcl-2蛋白的表达水平显著增高,差异有明显统计学意义(P＜0.05).结论 制动大鼠骨骼肌早期注射BMSCs,可引起抗凋亡蛋白Bcl-2表达水平上调、促凋亡蛋白Bax表达水平下调.

abstractsObjective To observe the effects of mesenchymal stem cells (BMSCs) on the expression of Bcl2 and Bax in atrophied muscles.Methods Immature rats (80～ 100 g) were anesthetized to collect marrow from their femurs and tibias.BMSCs were isolated from the marrow,cultured and purified using the whole bone marrow adherence method.Their right hindlimbs were immobilized fiom the thigh to the paw with the knee in extension and the ankle in plantar flexion.After the modeling,24 of the male rats were divided into a sham-operation group,a BMSC group and a phosphate buffer solution (PBS) group,each of 8.The BMSC and PBS groups were injected with either approximately 106 BMSCs or an equal volume of PBS into the belly of the soleus muscle after they had been immobilized for 48 hours,while the control group did not undergo any treatment except for the injection of PBS.All of the rats were sacrificed for analysis after 14 days.Results The BMSCs were mainly spindle cells,showing radial colony arrangement.They grew vigorously and could passage in a continuous and stable manner over 10 passages.At the 4th passage the BMSCs were positive for CD44 (95.84％) and CD90 (96.00％),but negative for CD34 and CD45.Western blotting assay demonstrated that the expression of Bax protein as measured in grey-scale value (0.41±0.08)in the BMSC group was significantly lower than in the PBS group (0.63±0.10),but significantly higher than in the control group (0.14±0.11) on average.The expression of Bcl-2 (0.47±0.14) was also significantly higher in the BMSC group than in the PBS group (0.22-± 0.13),but significantly lower than in the control group (0.81 ± 0.06).Conclusion Bone marrow mesenchymal stem cells can upregulate the expression of anti-apoptotic Bcl-2 protein and downregulate that of the apoptotic Bax protein when injected early into the belly of a muscle in an immobilized limb.