Effect of Exogenous Rb Gene on Expression of p21 Gene in Vascular Smooth Muscle Cells

The level of p21 mRNA and protein in cultured human umbilical arterial vascular smooth muscle cells were assayed by immunochemical staining and RT-PCR. The expression and phosphorylation status of Rb protein were examined by Western blot. It was observed that the senescent vascular smooth muscle cells exerted morphological changes with transmission electron microscope and characterized with beta-galactosidase staining. The flow cytometry was used for cell cycle analysis. Introduction of exogenous Rb gene could induce the expression of p21 gene leading to inhibition of phosphorylation of Rb protein. The senescent vascular smooth muscle cells at G0/G1 phase of the cell cycle were found following transfection of Rb gene recombinant adenovirus. These results show that exogenous Rb gene regulate cell cycle progression and promote cell senescence by induction of p21 gene expression.