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.