维生素E抑制同型半胱氨酸介导的血管平滑肌细胞增殖

目的 探讨在同型半胱氨酸诱导的血管平滑肌细胞(VSMC)增殖中,活性氧(ROS)的作用和维生素E的影响.方法 3H]-胸腺嘧啶脱氧核苷掺人法测定细胞DNA合成率,锥虫蓝染色计数细胞数量,DCF-DA荧光探针测定细胞内ROS.结果 (1)同型半胱氨酸诱导VSMC的DNA合成增加,促进细胞增殖和ROS水平升高;尽管半胱氨酸诱导VSMC内ROS水平升高,但是对细胞DNA合成和增殖无影响.(2)过氧化氢酶抑制同型半胱氨酸介导的VSMC内ROS升高,而对VSMC增殖无影响.(3)α-生育酚、β-生育酚均可抑制同型半胱氨酸诱导VSNC内ROS水平升高,但是只有α-生育酚显著抑制VSMC增殖.结论 ROS升高不是同型半胱氨酸诱导的VSMC增殖的原因之一.维生素E降低同型半胱氨酸诱导的VSMC增殖可能与抑制蛋白激酶C活性有关,而与它的抗氧化性无关.

Vitamin E inhibits homocysteine-mediated smooth muscle cell proliferation

OBJECTIVE: To investigate the role of reactive oxygen species (ROS) and the effect of vitamin E on proliferation of vascular smooth muscle cells (VSMCs) induced by homocysteine. METHODS: DNA synthesis in the VSMCs cells was measured using 3H]-thymidine incorporation assay, and the cell number determined by trypan blue method. The level of ROS in the cells was determined using DCF-DA as the fluorescence probe. RESULTS: Homocysteine promoted VSMC DNA synthesis, proliferation, and ROS production. Cysteine resulted in increased ROS production in VSMCs, but had no significant effect on DNA synthesis and cell proliferation. Catalase significantly inhibited ROS production induced by homocysteine, but did not significantly inhibited homocysteine-mediated proliferation of VSMCs. While alpha-tocopherol and beta-tocopherol both suppressed increased ROS production induced by homocysteine in VSMCs, only alpha-tocopherol significantly inhibited homocysteine-mediated VSMC proliferation. CONCLUSION: ROS is not associated with VSMC proliferation, and vitamin E-induced suppression of VSMC proliferation is probably related to protein kinase C inhibition.