应激对同型半胱氨酸关键代谢酶活性的影响

EFFECT OF STRESS ON THE ACTIVITIES OF KEY ENZYMES IN HOMOCYSTEINE METABOLISM

目的观察慢性束缚应激大鼠肝脏和肾脏内同型半胱氨酸甲基代谢途径中重要代谢酶活性的变化,探讨应激所致机体同型半胱氨酸代谢障碍的作用。方法采用慢性束缚应激方法建立大鼠应激模型;HPLC法检测血浆同型半胱氨酸、肝脏及肾脏甲硫氨酸合成酶和亚甲基四氢叶酸还原酶的活性;采用氨基酸自动分析仪检测甜菜碱高半胱氨酸甲基转移酶的活性。采用ELISA试剂盒测定血浆叶酸、维生素B6、维生素B12水平。结果束缚应激大鼠肝脏和肾脏细胞内同型半胱氨酸甲基化代谢途径中的甲硫氨酸合成酶,亚甲基四氢叶酸还原酶及甜菜碱高半胱氨酸甲基转移酶活性比对照组呈现总体下降的趋势。其血浆辅酶含量与对照组比呈现减低趋势。结论慢性应激所引起的肝脏细胞和肾脏细胞内同型半胱氨酸甲基化途径重要代谢酶活性降低,是引起应激机体高同型半胱氨酸血症的重要原因。

Objective To investigate the change of the activity of methionine synthase, methylenetetrahydrofolate reductase and betaine-homocysteine methyltransferase in liver and kidney of rats during stress process, so as to explore the effect of chronic restraint stress on methylation metabolism pathways of homocysteine in rats. Methods The model of restraint stress was adopted in our experiment. The activities of methionine synthase and methylenetetrahydrofolate reductase in liver and kidney were detected by high performance liquid chromatography; the activity of betaine-homocysteine methyltransferase was detected by automatic amino-acid analyzer. ELISA kits were used for determination of plasma folate, vitamin B6, vitamin BL2 levels. Results The activities of methionine synthase, methylenetetrahydrofolate reductase, betaine-homocysteine methyltransferase and the plasma vitamins in stress group were reduced compared with the control group （P〈0.05）. Conclusion The activities of homocysteine methylation pathways were decreased by chronic restraint stress, which may be an important cause for hyperhomocysteinemia.