Experimental study on effect of dexamethasone to the in-stent restenosis after vascular intervention

Objective To evaluate the effect of dexamethasone to the cultured rat thoracic aortic smooth muscle cells(SMC)in vitro,and explore the role on it's prevention and cure for the in-stent restenosis after vascular intervention.Methods The rat thoracic aortic SMC were harvested and cultured for six to ten passages.The cultured SMC were synchronized and then restimulated to enter the cell cycle,and treated with incremental concentrations of dexamethasone or without dexamethasone as control.The proliferative assay was performed with MTT method in the different time points after treatment.RT-PCR was performed to assay the level of proliferating cell nuclear antigen(PCNA)mRNA.Results 1.Dexamethasone progressively inhibited rat aortic SMC proliferation in a concentration-dependent fashion.The A value was statistically significant for different concentrations(F=36.02,P＜0.001).The effect was not significant for dexamethasone concentrations either between 10~(-6)and 10~(-5)mol/L(P=0.065)or between 10~(-11)mol/L and control group(P= 0.567).2.RT-PCR suggested dexamethasone significantly decreased rat aortic SMC PCNA mRNA transcription in a concentration-dependent fashion.Statistical analysis indicated F=15.407 and P＜0.001 by ANOVA. Comparing to the control,the corrected A value was not statistically significant at 10~(-9)or 10~(-11)mol/L groups by post hoc analysis.Conclusions Dexamethasone inhibits rat aortic SMC proliferation in a concentration- dependent fashion.The data suggest that effective action concentration is 10~(-7)mol/L with persistent time up to 96 hours or more.Dexamethasone may play the inhibit role to SMC at lower concentration with prolonging action time.