The Research Of BMSCs Used To Myocardial Injury After Cardiomyocyte-like Cells Induction

[Objective] Research for the rat Bone marrow mesenchymal stem cells (Bone mesenchymal stem cells, BMSCs) under the influence (5-azacytidine,5-aza) directional for different states of cells (including pluripotent stem cells, multipotent stem cells or precursor stem cells, multiple stages of adult cardiomyocyte-like cells). The the various stages cells were transplanted into myocardial injury model in rats. Then observ different developmental stages of tissue repair ability of the cells differences and whether already nest.To find the most suitable time and status of transplanted cells.[Methods] We get BMSCs In vitro, labeled with GFP transgenic, and then directional induction to cardiomyocyte-like cells. And respectively measure Cardiac troponin-T(cTn-T), connexin43(Cx43) and a-sarcomeric actin(a-SCA) in induced0,3,7,14,21and28-day. The40rats were randomly divided into five groups:BMSCs group;3-day group;7-day group;21-days group and model group. We eatablished the rat myocardial ischemic injury animal model by ISO (255mg/kg) subcutaneously injected. After successfully modeled, GFP-labeled cells injected via the tail vein of every rat with3×106cell/kg.Then tested the changes of ultrasound heart function of rat on the2-week after the transplant and the4-week after the transplant.When in4-week heart tissue of the treatment and model groups animals were taken to make pathological sections to observe difference between the treatmen groups.[The results]①BMSCs can adherent growth and have the differentiation capacity. After labeled with GFP transgenic.BMSCs have the ability of normal growth and differentiation. BMSCs express CD34-/CD45-/CD73+/CD105+②etect cTn-T, Cx43and a-SCA marker expression in the induction process of BMSCs. Each marker expression was negative of uninduced BMSCs. The a-SCA positive expression, we can find a small amount of brown cells after induced3days. Each marker can positive expression after induced7days.Each marker achieve maximum after induced21days.③Green fluorescence was find in the myocardial tissue on4-week.It proves that precursor stem cells homing has occureed, and to participate in the reconstruction of the body.④Difference in2-week and4-week go ultrasound examination BMSCs group and induction of7,21-days group have no significant differences(P>0.05),3-day group and model group compared are very significantly different(P<0.01).3-day group and BMSCs group,7-day group,21-day group with significant differences (P<0.05). Histological analysis show that myocardial stripes clear, myocardial closely arranged,have no myocardial edema,hyperemia and hemorrhage on3-day group Myocardial local bleeding, myocardial stripes unclear, cardiac disorder, myocardial edema, and myocardial fibrosis on. Myocardia significant congestion, myocardial cell swelling significantly, myocardial stripes disappear,loose arrangement on modle group. Myocardial injury has been improved after cells transplantation,especially3-day group.[Conclusion]①stablished system and technology platform to identify and GFP-mark of rat BMSCs in vitro.②After induced, the cell morphology is change gradually, cells begin to express cell markers a-SCA after3days and begin to express cTn-T and Cx43after7days. The three markers of myocardial cells express increased gradually and acheave peak after21days.The research of BMSCs differentiation in the different stages of the cell transplantation and tissue damage repair to the differences.Cardiomyocyte-like cells induction3-daygroup Ultrasound and histopathology than the other group were obviously improved. After3days of induction,BMSCs have part of the secretory function, but have not yet differentiated into cardiomyocytes. After the injection it has characteristics of homing to the site of injury and continued differentiation of stem cells into cardiomyocytes, alternative complement injury or death myocardial cells, to promote tissues and organs function, while avoiding the disadvantages of stem cell differentiation of transplantation to the mesenchymal cells.3-day group is the most suitable transplanted cells.