The Antiapoptotic Effect Of Bone Marrow Mesenchymal Stem Cells On Cardiomyocyte Apoptosis Is Enhanced By Hypoxia Precondition

Objective To investigate whether the protective effects 0f bone mesenchymal stem cells(MSCs) on hypoxia-induced cardiaomyocytes apoptpsis could be enhanced by the hypoxia precondition.,and to explore the possible mechanism .Methodsâ‘ The animals and cell for experiment:Sprague-Dawley(SD)rats,SPF;cardiaomyocytes ,H9c2(2-1),was bought from Boster company of WuHan.â‘¡The preparation of MSCs conditioned medium: The fourth Generation of MSCs co-cultured with L-DMEM without fetal bovine serum(FBS) , under the CO₂ incubator or hypoxia incubato respectively, then collect the medium and centrifugal, the supernatant was the conditioned medium of MSCs.â‘¢Cardiaomyocytes were divided into 4 groups in random : Cardiaomyocytes culture under normal condition (normal group) ; Cardiaomyocytes culture under hypoxia condition alone (hypoxia-only group) ; Cardiaomyocytes co-cultured with conditioned medium of MSCs under normal condition (MSCs group); Cardiaomyocytes co-cultured conditioned medium of BMSCs under hypoxia precondition (MSCs- hypoxia group) .â‘£Experiment evaluation: Cell viability and the cell apoptosis was measured by MTT assay and Annexin V-FITC/PI staining respectively. The protein expression of Bax and Bcl-2 were detected by immuno-histochemisty staining.Resultâ‘ Cells cultured in vitro adhered obviously after 24 h,cells were many kinds of shape such as round,fusiform,and irregularity;after passages,the form of cells was becoming to be conformity,being fusiform.The reproductive activity of MSCs cultured in vitro was strong, MSCs grew colony and the shape of cell colony was on"swirl".â‘¡Compared with normal group ,the cell viability of MSCs group was reduced greatly(P<0.05),which suggested that hypoxia for 72 hours produced a successful model of cardiomyocytes hypoxia .Compared with hypoxia-only group and MSCs group, the cell viability of MSCs-hypoxia group was significantly increased (P<0.05).â‘¢Compared with hypoxia-only group and MSCs group,the cardiomyocytes apoptosis rate of MSCs- hypoxia group was reduced(P<0.05) .â‘£Compared to other groups ,Bcl-2 was up regulated and Bax was down regulated in the MSCs- hypoxia group(P<0.05) .Conclusion Hypoxia precondition could enhance the antiapoptotic effect of MSCs on cardiomyocytes apoptosis induced by hypoxia ,which increasing the ratio of Bcl-2/Bax .