金属硫蛋白抑制同型半胱氨酸诱导的大鼠血管成纤维细胞激活

目的:观察外源性金属硫蛋白(MT)和ZnCl₂诱导内源性MT生成对同型半胱氨酸(HCY)激活大鼠血管成纤维细胞增殖的影响, 以探讨MT拮抗HCY血管损伤的可能机理。方法:采用³H]-胸腺嘧啶(³H]－TdR)和³H]-脯氨酸(³H]－Pro)掺入法测定细胞增殖及胶原生成, 自动生化分析仪测定乳酸脱氢酶(LDH)漏出量, 台盼蓝排斥法计算细胞存活率, 并用¹⁰⁹Cd]-血红蛋白饱和法检测细胞MT的含量。结果:HCY50、100、500μmol/L呈浓度依赖性刺激血管成纤维细胞增殖, 胶原合成和分泌(P＜0.05或P＜0.01), 500μmol/LHCY使细胞LDH漏出量增多, 细胞存活率降低。MT1×10^-5mol/L、1×10^-4mol/L与500μmol/LHCY共孵育组与单纯HCY组比较, ³H]-TdR、³H]-Pro掺入、胶原分泌降低, LDH漏出量减少(P＜0.05或P＜0.01)。ZnCl₂预处理诱导细胞MT含量增加(P＜0.05), 而ZnCl₂处理与HCY50、100、500μmol/L共孵育组³H]－TdR和³H]－Pro掺入, 胶原分泌、LDH漏出量都明显低于单纯HCY组细胞, 且细胞存活率高于单纯HCY组(P＜0.05或P＜0.01)。结论:HCY刺激血管成纤维细胞增殖与胶原合成, MT无论外源应用或内源性诱导生成均能有效拮抗HCY的上述作用。MT对HCY作用的拮抗效应可能是其血管细胞保护的机理之一。

Metallothionein inhibits rat vascular fibroblasts activation induced by homocysteine

AIM:To study the effects of exogenous metallothionein (MT) and ZnCl₂-induced MT production on biological action of homocysteine(HCY)in vascular fibroblasts.METHODS:³H]-TdR, ³H]-Pro incorporation and LDH leakage were measured, the cellular viabilities were calculated by trypan blue exclusion test and the intracellular contents of MT were assayed by ¹⁰⁹Cd]-hemoglobin saturation method in cultured rat vascular fibroblasts.RESULTS:Proliferation, collagen production of vascular fibroblasts in HCY-treated group were significantly increased compared with control group in a concentration-depedant manner. HCY (500 μmol/L) increased LDH leakage and decreased the cellular viabilities (P＜0.05 or P＜0.01). ³H]-TdR incorporation, ³H]-Pro incorporation, collagen secretion and LDH leakage were all decreased in MT (1×10^-5 mol/L, 1×10^-4mol/L) plus HCY(500 μmol/L) incubated group, compared with HCY alone group, respectively (P＜0.05 or P＜0.01). MT content in ZnCl₂ pretreatment group was increased compared with control group. Proliferation, collagen production and LDH leakage in HCY group pretreated with ZnCl₂ were decreased whereas the cellular viabilities were increased compared with HCY alone group.CONCLUSIONS:The results shows that HCY induces proliferation and collagen production of vascular fibroblasts. Both exogenous MT and endogenous MT induced by ZnCl₂ inhibite the above-mentioned effects of HCY on vascular fibroblasts. MT inhibites vascular fibroblast activation induced by HCY, which may be related to its vascular protection.