Effect of Extractive of Pericarpium Trichosanthis on Cell Cycle of Rat Vascular Smooth Cell Proliferation Induced by PDGF-BB

Aim To investigate the effect of extractive of pericarpium trichosanthis(EPT) on cell cycle of rat vascular smooth muscle(VSMC) proliferation induced by platelet-derived growth factor-BB(PDGF-BB) and to probe especially into its mechanism.Methods VSMC from the thoracic aorta of SD rats were cultured by tissue explant method.Effect of EPT(10,20 and 30 mg/L) on PDGF-BB-induced VSMC proliferation was assessed by 3H-TdR method,the cell cycle was analyzed by flow cytometry,expression of c-fos and c-myc mRNA in VSMC were detected by real-time quantitative reverse transcription-polymerase chain reaction(real-time RT-PCR).Results PDGF-BB could significantly increase the rate of 3H-TdR incorporation(P0.01) and the percentage of S phase cells,and degrade the G0/G1 phase cell percentage in the cell cycle(P0.01).At the same time,PDGF-BB could up-regulate c-fos and c-myc mRNA expression(P0.01).Addition of EPT(10,20 and 30 mg/L) markedly inhibited the PDGF-BB-induced proliferation of the VSMC(P0.01),decreased the S phase cell percentage and upgraded the G0/G1 phase cell percentage in the cell cycle,EPT could also depress the elevated expression of c-fos and c-myc mRNA indcued by PDGF-BB.Conclusions EPT could inhibit the VSMC proliferation induced by PDGF-BB through preventing the transformation of the G0/G1 phase cell to S phase cell in the cell cycle.The mechanism may be related to its down-regulatory effect on c-fos and c-myc mRNA expressions.