Effect Of GATA-6 In Inhibiting The Proliferation Of Pulmonary Vascular Smooth Muscle Cells Induced By Endogenous Carbon Monoxide

Objective To investigate the effect of GATA-6 of endogenous carbon monoxide(CO) inhibited proliferation of pulmonary vascular smooth muscle cells(PVSMCs) induced by platelet-derived growth factor-BB(PDGF-BB).Methods Tissue mass was cultured done to get PVSMCs artery in SD rats, and these PVSMCs were divided into 5 groups: Group 1 was the normal or control group; Group 2 was the platelet-derived growth factor-BB(PDGF-BB 20ng/ml) group; Group 3 was treated by platelet-derived growth factor-BB and Hemin(10μmol/l), a inducer of HO-land can promote CO product; Group 4 was treated with platelet-derived growth factor-BB and Hemin(20μmol/l); Group 5 was treated with platelet-derived growth factor-BB and Hemin(30μmol/l). At 8 hours, 16 hours and 24 hours after the treatment, the proliferation of PVSMCs were detected using 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphemyl-2H-tetrazolim bromide(MTT) method, DNA synthesis was detected by [3H]thymidine incorporation, the relative amount of HbCO in media was detected and GATA-6 mRNA expression was detected by reverse transcription polymerase chain reaction (RT-PCR).Results 1) PDGF markedly induced the proliferation of PVSMCs. There are statistically significant differences between the results of MTT at 8 hours and 24 hours (0.0278±0.0076 vs 0.0588±0.0054, p＜0.05), the maximum of proliferation was at 24 hours. CO could inhibited the PVSMCs proliferation induced by PDGF. PVSMCs proliferation of Groups 5 with high concentration of Hemin(30μmol/l) at different times showed statistically significant differences (0.0180±0.0015, 0.0157±0.0055, 0.0092±0.0047, p＜0.05). Significant differences were found in the groups with different concentration of Hemin at 24 hours (0.0350±0.0054, 0.0588±0.0054, 0.0252±0.0064, 0.0173±0.0047, 0.0092±0.0047, p＜0.05). These data implicated that CO inhibited the proliferation of PVSMCs induced by PDGF in a dose-dependent and time-dependent manner. 2)PDGF could promoted the DNA synthesis of PVSMCs, the [3H]thymidine incorporation showed significant differences in different times (222.00±29.32 vs 752.00±142.33 vs 1112.00±120.51, p＜0.05), CO inhibited the DNA synthesis in a dose-dependent manner. 3)PVSMCs product the endogenous carbon monoxide induced by Hemin in a time-dependent and concentration-dependent manner. 4)PDGF induced markedly the down-regulation of GATA-6 expression at 2 hours, and returned to the previous level after 6 hours. The down-regulation could been inhibited by CO in a dose-dependent manner. The inhibition of GATA-6 down-regulation was noticeable in group with high concentration of Hemin(30μmol/l), however, the inhibition of CO returned previous level after 6 hours. Conclusions PVSMCs product the endogenous carbon monoxide induced by Hemin in a time-dependent and concentration-dependent manner. PDGF can stimulate the proliferation and DNA synthesis of PVSMCs and simultaneously, inhibited the expression of GATA-6 mRNA. CO can inhibit the proliferation and DNA synthesis of PVSMCs induced by PDGF in a dose-dependent and time-dependent manner and inhibit the down-regulation of GATA-6 mRNA induced by PDGF in a dose-dependentmanner. The study suggested that CO can effectively inhibit PVSMCs proliferation, and the mechanism maybe through the regulation of GATA-6 gene expression.