叶酸拮抗同型半胱氨酸诱导的内皮细胞凋亡的作用机制

Mechanism underlying the antagonistic effect of folic acid on homocysteine-induced apoptosis in endothelial cells

目的:明确同型半胱氨酸(Hcy)对内皮细胞凋亡的影响以及叶酸的拮抗作用,阐明Bax和Bcl-2在同型半胱氨酸诱导内皮细胞凋亡及叶酸拮抗中的作用。方法:用不同浓度的Hcy处理内皮细胞后,应用末端转移标记技术(TUNEL)以及Annexin V/PI染色加流式细胞术了解细胞凋亡状态,免疫组化方法检测Bax、Bcl-2的表达。结果:Hcy能促进细胞凋亡,叶酸具有拮抗作用。Hcy能促进细胞Bax、Bcl-2的表达,上调Bax/Bcl-2比值,叶酸能减少细胞表达Bax及Bcl-2,下调Bax/Bcl-2比值。结论:Bax、Bcl-2参与了Hcy诱导内皮细胞凋亡以及叶酸拮抗作用的过程。

AIM： To investigate the effects of homocysteine （Hcy） on apoptosis in SV40 -transformed aortic rat endothelial cell line and the anti - apoptosis effects of folic acid. METHODS： Cells were treated with different concentrations of Hcy and folic acid, apoptosis was detected by TUNEL and annexin - V/PI staining methods. Immunohistochemical assay was used to examine the expression of Bax and Bcl - 2 in all groups. RESULTS ： Both armexin - V/PI staining and TUNEL method showed that Hcy increased endothelial apoptosis in a dose - dependent manner, while folic acid reduced cell apeptosis. Hcy increased expression of Bax and Bcl -2 in endothelial cells, and folic acid decreased it. Bax/Bcl -2 ratio in 0. 5 mmol/L Hcy and 5.0 mmol/L Hcy group were upregulated compared with control group （ P 〈 0. 05 and P 〈 0. 01, respectively）. Addition of 0. 1 mmol/L folic acid decreased Bax/Bcl -2 ratio compared with the corresponding group without folic acid （P 〈0. 05）. Correlation analysis showed a strong relation between Bax/Bcl -2 ratio and apeptotic rate （P 〈 0. 01 ）. CONCLUSION： Folic acid attenuates the apeptosis induced by Hcy in endothelial cells. Hcy may promote endothelial cell apeptosis via upregulation of Bax/Bc1-2 ratio, which can be partially antagonized by folic acid.