同型半胱氨酸抑制人血管内皮细胞精氨酸转运  

Homocysteine inhibits L-arginine transport in human vascular endothelial cells

作　　者：李夏[1] 刘乃奎[1] 蒋宏峰 庞永政[1] 唐朝枢[1] 杜军保[3] 

机构地区：[1]北京大学第一医院心血管病研究所,北京100034 [2]北京大学第一医院基础医学院生理系学 [3]北京大学第一医院儿科,北京100034

出　　处：《北京大学学报（医学版）》2002年第2期159-162,191,共5页Journal of Peking University:Health Sciences

基　　金：国家自然科学基金项目 ( 39870 35 5 ;39730 2 2 0 )~~

摘　　要：目的 :观察同型半胱氨酸 (homocysteine,HCY )对人脐静脉内皮细胞左旋 精氨酸 一氧化氮 (L arginine NO)途径的影响及HCY致血管损伤的机制。方法 :将培养的人脐静脉内皮细胞随机分 4组 (每组n =6 ) ,加入HCY使终浓度分别为 0、0 .0 1、0 .1和 1mmol·L- 1 ,培养 12h后 ,检测内皮细胞存活率、乳酸脱氢酶 (lactatedehydro genase ,LDH)漏出及细胞L arginine转运、一氧化氮合酶 (nitricoxidesynthase,NOS)活性和亚硝酸盐 (NO2 )生成的变化。结果 :与对照组相比 ,0 .1mmol·L- 1 HCY增加LDH漏出 ,1mmol·L- 1 HCY降低细胞存活率 ,增加LDH漏出 ;0 .1、1mmol·L- 1 组NO生成显著降低 ,但仅在 1mmol·L- 1 组才降低NOS活性。HCY呈浓度依赖地降低内皮细胞L arginine转运 ,0 .0 1mmol·L- 1 HCY即明显抑制细胞L arginine转运速率 ,0 .1、1mmol·L- 1 HCY不仅显著降低细胞L arginine最大转运速率 ,而且增高米氏常数 ,降低了转运效率。 结论 :HCY损伤人血管内皮细胞L arginine NO途径 ,尤其是抑制细胞L arginine转运 ,这可能是HCY导致心血管疾病时心血管功能和结构损伤的重要机制之一。Objective: To observe the effect of homocysteine (HCY) on L arginine/NO pathway of human umbilical venous endothelial cells (ECs) and to investigate the mechanism of vascular damage induced by HCY. Methods: The cultured human umbilical venous ECs were randomly divided into four groups (each n =6). The ECs were then exposed to the presence of HCY [0 (as control), 0.01, 0.1 and 1.0 mmol·L -1 , respectively] for 12 hours. Cell viability and the activity of lactate dehydrogenase (LDH) leaked from cells were determined, and the changes of L arginine transport ,nitric oxide synthase(NOS) activity and nitric oxide(NO) production from ECs were measured.Results: Compared with control group, viability and released LDH activity of ECs were not significantly changed in 0.01 mmol·L -1 HCY group, whereas LDH leakage in 0.1 mmol·L -1 HCY group increased. High concentration of HCY (1.0 mmol·L -1 ) induced an LDH serious leakage from ECs, and an obvious decrease in the cellular viability. Low concentration of HCY (0.01 mmol·L -1 ) had no effect on NO production of ECs; medial and high concentrations of HCY (0.1 and 1.0 mmol·L -1 ) lowered significantly NO production. But only high concentration of HCY decreased cellular NOS activity, low and medial concentrations of HCY did not. HCY inhibited significantly L arginine transport of ECs in a concentration dependent manner. The L arginine transport in 0.01 mmol·L -1 HCY group was decreased. Incubation of ECs with 0.1 and 1.0 mmol·L -1 HCY not only markedly lowered V max for L arginine transport, but also obviously elevated the value of K m, so L arginine transport efficiency was potently decreased. Conclusion: The data show that HCY induces dysfunction of L arginine/NOS/NO pathway in vascular ECs,and potently inhibits L arginine transport, suggesting that the effect of HCY inhibited cellular L arginine transport could be one of the pathogenetic mechanisms, by whi

关 键 词：同型半胱氨酸 血管内皮细胞 精氨酸 一氧化氮合酶 转运 

分 类 号：Q591.2[生物学—生物化学]