Effects Of High Pressure On Proliferation And Apoptosis Of Vascular Smooth Muscle Cells Of Organ-cultured Artery In Vitro

Objective: To explore the effects of mechanical factors on vascular remodeling the changes of morphorlogy and function of vascular smooth muscle cells(VSMCs) were studied in an intact artery under high pressure. Materials and methods: Common carotid arteries of pigs were cultured at 37 with Dulbecco's Modified Eagle Medium containing 10% newborn calf serum at a constant flow rate of no more than 6ml/h within 1, 4 and 7 days under high pressure(160mmHg) and middle pressure(lOOmmHg) in a new vascular organ-cultured system in vitro. The changes of structure of VSMCs were observed by light and transmission electron microscopy. The changes of phenotype and ability of secretion, as well as proliferation and apoptosis of VSMCs under high pressure were studied by immunohistochemistry, fluorescent staining and computer image processing methods. Results: (1)The expression of a-actin of VSMCs was downregulated within 7 days. The phenotype of VSMCs converted from contractile phenotype into synthetic phenotype.(2)The proliferation rate of VSMCs increased continuously while apoptosis rate increased at first and then decreased under high pressure. (3)Growth factors such as PDGF-A and TGF- 3 1 were prone to increase. (4)The expressions of P53 protein and Bcl-2 protein increased within 7 days in group of high pressure. Bax protein increased at first and then decreased within 7 days. Conclusion: The results revealed that VSMCs underwent remodeling within 7 days under high pressure. VSMCs underwent a transformation from contractile phenotype into synthetic phenotype. The proliferation of VSMCs was increscent while the apoptosis rate of VSMCs increased at first and then decreasedunder high pressure. The interrelated proteins, such as PDGF-A, TGF-β1 , Bcl-2 and Bax et al, have important effects on proliferation and apoptosis of VSMCs.