The Role Of Serum Response Factor In Hypoxia-induced Rat Pulmonary Artery Smooth Muscle Cell Proliferation

Objective:To explore the role of serum response factor in hypoxia induced rat pulmonary artery smooth muscle cell proliferation.Methods:1.The rat PASMCs were isolated and cultured.Identification of rat pulmonary artery smooth muscle cells were identified by immunohistochemical staining.2.The effect of oxygen concentration on cell proliferation: the PASMCs were cultured in normoxia(21%O2),hypoxia(10%O2、5%O2、2%O2 and 1%O2)condition,respectively.The cell proliferation was measured by methy1 thiazolyl tetrazolium(MTT)method.After 24 hours,48hours and 72 hours in different hypoxia conditions,the m RNA expression of SRF was detected by RT-PCR and the protein expression of SRF was detected by immunohistochemical staining and Western-blot.Results:1.The PASMCs cultured in vitro were observed.They were found that the shapes were round.After 3 days,it was found that the shape of PASMCs were spindle and cytoplasmic elongation.Immunocytochemical results demonstrated that the nuclei were dyed pale blue and cell plasma were tan.2.The PASMC cultured in group of 1%O2 proliferated rapid significantly showed by depicting the cell growth curve and MTT method.3.The PASMC proliferation after transfecting with SRF si RNA,reduced in normoxia+SRF si RNA group compared with control group(p < 0.05).After transfected with SRF si RNA,the PASMCs activity in hypoxia group decreased significantly;however,after transfected with SRF si RNA,PASMCs activity in hypoxia group had no significant difference compared with that in control group.The m RNA and protein expressions of SRF were detected by RT-PCR,immunocytochemical staining and Western-blot.The results showed that the m RNA and protein expressions of SRF decreased significantly after transfecting with SRF si RNA.Conclusion: Hypoxia can increase the expression of SRF in rat PASMCs and promote the rat pulmonary artery smooth muscle cell proliferation.