Expression Of PCNA And P16 In The Common Carotid Artery Of Rats After Balloon Injury And Intervention Of ATRA

ObjectiveTo investigate the dynamic change of PCNA and P16 in the common carotid artery of rats after balloon injury and their effect on intimal proliferation.To evaluate the effect of ATRA on intimal proliferation and the expression of PCNA and P16 after balloon injury.MethodsThe 64 male SD rats were randomly divided into three groups:Sham operation group(n=8),ballon injury group(n=32,including 2,7,14,28-days subgroup),ATRA administration group(n=24,including control subgroup,normal-dose subgroup, high-dose subgroup).The balloon injury model of rat common carotid aortic artery was established.HE staining was used to observe the ratio of intima-media(I/M) thickness of the injured arteries with optical microscopy.The expression level of PCNA and P16 mRNA were examined with the method of RT-PCR.The expression level of PCNA and P16 protein was examined with the method of immunohistochemistry.ResultsThe intimal proliferation could be found in injured arteries ,both the intima thickness(148.03±5.69vs1.23±0.13,P<0.05)(μm )and the intima-media ratio(2.30±0.05vs 0.02±0.002, P<0.05) was found reaching the peak at the 28th day.The level of PCNA mRNA was found increasing and the PCNA mRNA was found reaching the peak at 7th day after balloon injury ( 1.29±0.07vs0.21±0.02,P<0.05), but the expression changes of P16 mRNA was inapparent after vascular balloon injury. The expression of PCNA protein was found increasing after balloon injury,the protein was observed to reach the peak at the 7th day(40.74±1.66 vs 1.26±0.06,P<0.05), but the expression changes of P16 protein was inapparent after vascular balloon injury. ATRA inhibited, in a dose-dependent manner,the intimal proliferation and the expression of PCNA mRNA and PCNA protein. ATRA increased , in a dose-dependent manner,the expression of P16 mRNA and P16 protein.ConclusionsThe dynamic change of PCNA mRNA and PCNA protein after balloon injury plays an important role in intimal proliferation.The expression of PCNA is concerned with intimal proliferation after balloon injury. ATRA can effectively repress intimal proliferation after vascular injury , which may be associated with inhibting the proliferation of vascular smooth muscle cells through down-regulating the expression of PCNA and upregulating that of P16.