The Study Of The Role Of Myocardin In Differentiation Of Vascular Smooth Muscle-Like Cell

Background Hyperlipidemia is the most important risk factor of atherosclerosis (AS).The proliferation and synthesis of extracellular matrix of the smooth muscle cell is an important link in the development of atherosclerosis (AS).For a long time many scholars believe that the vascular smooth muscle cells in the AS plaques derived from the migration and proliferation of the membrane smooth muscle cells in, but in recent years, research confirmed that inhibition of their migration and proliferation can not effectively prevent the occurrence and development of AS. A considerable amount of research included that bone marrow and peripheral blood progenitor cells may be involved in the formation of AS. In the process of differentiation of the smooth muscle progenitor cells to smooth muscle cells, myocardin found so far is the most crucial promote vascular smooth muscle cell differentiation factor. The introduction of myocardin gene into certain non-smooth muscle cells activated the expression of a series of smooth muscle differentiation marker genes and protein. And using RNA interference technology, inhibitory of myocardin gene expression can reduce the smooth muscle cell-specific protein kinase-related telokin promoter activity in the process of differentiation. Defect of myocardin gene can lead to complete blocking of vascular smooth muscle cell differentiation of fetal rat. Further details indicated that myocardin is necessary for the differentiation of progenitor cells to the smooth muscle cells.So we made assumptions: bone marrow and peripheral blood cells are an important source of smooth muscle cells in the AS plaque of one of the smooth muscle cells to the smooth muscle cells. Myocardin play a key role in the process of plaque formation and the expression of myocardin gene may impact the AS formation, and the suppression of the expression of myocardin gene may control the progress of AS plaque.Objective Detect the mRNA of myocardin,α-actin, SM-22 to investigate the importance of myocardin in differentiation of bone marrow mesenchymal stem cells(BMSC)into smooth muscle cells(SMC) in vitro under high concentrations of FBS(20%) and PDGF-BB(50ng/ml), and to investigate the difference of the effect of the two groups. Methods Firstly, mouse BMSCs were isolated and purified from bone marrow, and then induced in two groups: (1) only FBS (20%) were added to the BMSCs; (2) 50ng/ml PDGF-BB and. FBS (20%) were added. The cells of each group were cultured for 0,4, 8, 12 days respectively with a positive control SMCs. At the end, RT-PCR was used to detect the mRNA expression of myocardin,α-actin, and SM-22.Results 1.The expressing of the mRNA of myocardin,α-actin, and SM-22 increased gradually and remaind stabilization since it had achieved the highest point at 8days after induction 2. The expression of mRNA is higher in the second group than the first one. 3. Statistically there was significance in different induction times and groups (p<0.05).Conclusions 1.Myocardin plays an important role in differentiation of BMSC into SMC. 2. The combination effect of PDGF-BB (50ng/ml) and FBS (20%) was prior to that of FBS (20%) alone.