RESUMEN
Objective To explore the underlying molecular mechanisms of estrogen induced apoptosis of synthetic vascular smooth muscle cells (VSMCs). Methods Cultured VSMCs on passage 3 were divided into three groups: 17?-estradiol (E-2) group, p38 inhibitor group (SB+E-2) and control group. With treatment for 72 hours,the apoptosis of cells was quantified by measuring the intracellular nucleosomes with ELISA; expressions of total p38, phospho-p38 and myocyte enhancer factor-2 (MEF2) were analyzed by Western blotting, with a confirmative immunohistochemical staining for MEF2. Results Compared with that of control cells, the rate of apoptosis in VSMCs grown in E-2 was significantly increased, with up-regulations of total p38, phospho-p38 and MEF2. These effects of E-2 were blocked in SB+E-2 group in which the rate of cell apoptosis and expression of p38 had no obvious change compared with that of control group, while the expression of p-p38 and MEF2 was decreased. Immunohistochemical staining showed that MEF2 was mainly located in cellular nucleus, and its expression was increased in E-2 group but decreased in SB+E-2 group. Conclusion Estrogen may induce apoptosis of synthetic VSMCs through p38 pathway-dependent up-regulation of MEF2.