Effects of hyperhomocysteinemia on neointimal hyperplasia in balloon-injured rat carotid arteries

Objective:To study the effect of diet-induced hyperhomocysteinemia on the intimal hyperplasia in a rat model of carotid artery balloon injury.Method:Thirty twelve-week-old male Spraque-Dauley rats were divided randomly into three groups(n=10 per group): the control group (ordinary feed),low dose methionine(LM) group containing 1.2% methionine in feed ,high dose methionine(HM) group containing 2% methionine in feed. After 4 weeks on their respective diets,all animals underwent left common carotid artery balloon denudation and right common carotid artery was kept as control(balloon injury were not performed).Plasma homocysteine levels were determined by high-performance liquid chromatography(HPLC) with fluorescence detection. The morphology of arteries intima and media was studied by optical microscopy,electron microscopy and image analysis system.Result:The levels of HCY in LM(24.55±2.21μmol/L) and HM(55.52±4.78μmol/L) group were significantly higher than those in control group(5.45±1.21μmol/L)(P0.01).The neointimal hyperplasia in LM and HM groups were more obvious than in the control group. The results of image analysis showed that intimia hyperplasia developed in all balloon-injured ateries in both control and methionine-treated animals. The intimal area and intimal/media area ratio were increased by 87%(P0.01),98%(P0.05)and 97%(P0.01),109%(P0.01),luminal areas were also significantly smaller(45% and 55%,P0.05)in the low dose-methionine-treated and high dose-methionine-treated animals as compared to the control animals respectively. Conclusion: Diet-induced hyperhomocysteinemia can exacerbate intimal hyperplasia after denuding injury, that means hyperhomocysteinemia a likely risk factor for postangioplasty restenosis.Author′s address Department of Cardiology,Union Hospital,Tongji Medical College, Huazhong University of Science Technology,Wuhan Hubei,430022