Effects Of Bone Mesenchymal Stem Cells On The Expressions Of Bcl-2 And Bax In The Atrophy Muscle Induced By Immobilization

Objective: To observe the effects of bone mesenchymal stem cells(BMSCs) on the expressions of Bcl-2 and Bax in the atrophy muscle induced by immobilization.Methods: Rats(80-100g) were anesthetized to collect marrow from the femurs and tibias.BMSCs were isolated, cultured and purified by the whole bone marrow adherence method.Rats’ right hindlimb were immobilized from thigh to foot, resulting in immobilization of the knee in the extension position, and the ankle in the plantar flexion position. 24 male model rats were divided into 3 groups. BMSCs group were injected with 1×106 BMSCs into the belly of soleus muscle after immobilizing for 48 hours. PBS group were injected with equal PBS. Control group did not undergo any treatment except for equal PBS. All rats were sacrificed for analyzing after 14 days.Result: BMSCs from rats were spindle cell-based, showing radial colony arrangement.Cells kept strong growth and could passage in continuous and stable manner over 10 passages. At the fourth passage, BMSCs were positive of CD44(92.84%) and CD90(92.00%), but negative of CD34(3.84%) and CD45(5.25%). Western blot assay results demonstrated that the expression of Bax protein(0.41±0.08)in BMSCs group was lower when compared with PBS group( 0.63±0.10)(p<0.05),but higher than control group(0.14±0.11)(p<0.05). Bcl-2( 0.47±0.14) was significantly higher in BMSCs group when compared with PBS group( 0.22±0.13)(p<0.05), but lower than control group(0.81±0.06)(p<0.05).Conclusion Bone marrow mesenchymal stem cells can upregulate anti-apoptotic Bcl-2protein expression and downregulate apoptotic Bax protein expression when early injected into the belly of soleus muscle of immobilized limb.