Influence of All-trans Retinoic Acid on the Expression of Cdk2 and Proliferation of Vascular Smooth Muscle Cells in Carotid Atherosclerosis in Rabbits.

Objective To investigate the influence of all-trans retinoic acid(ATRA) on the neointimal formation,vascular remodeling,the expression of Cdk2 in carotid atherosclerosis in rabbits.Methods Thirty-six New Zealand rabbits were randomly divided into 3 groups: normal group(n=12),control group(n=12) and ATRA-treated group(n=12).The control group and ATRA-treated group were fed with high-cholesterol diet and two week's later they were induced into carotid atherosclerosis using air-drying technic.ATRA-treated group was predosed with ATRA by gavage 3 days before surgery.All rabbits were killed one week or four weeks after surgery.Using immunohistochemiscal staining,the harvested target vessels were measured the protein expression of Cdk2 and proliferation cell nuclear antigen PCNA.Meanwhile vessel morphological measurement was taken for all target vessels.Results(1) In normal group,Cdk2 and PCNA could not be detected in the target vessels.(2)In control group,there was a distinct intima hyperplasia and narrowed luminal area at six weeks after surgery.The expressions of PCNA and Cdk2 were significantly intense.(3) In ATRA-treated group,the Cdk2 expression was markedly lower than that in control group.And there was an outstanding smaller intima/media area ratio and larger luminal area in ATRA-treated group.(4) The PCNA expression and Cdk2 expression are in remarkable positive correlation.Conclusions ATRA could inhibit Cdk2 expression and VSMC proliferation,therefore it could reduce intima proliferation and elicit favorable geometric remodeling of the carotid atherosclerosis in rabbits.