Expression Of MMP-2 And MMP-3 In Hyperhomocysteinemic Rats

Objective:To establish a rat model of hyperhomoeysteine (Hhcy) and investigate the expression of blood homoeysteine (Hcy),matrix metalloproteinases-2 (MMP-2) and matrix metalloproteinases-3(MMP-3) before and after modelling to explore how Hhcy induces atherosclerosis.Methods:30 healthy male Wistar rats were selected and randomly divided into three groups: control group,methionine group and intervention group. Control group was fed on ordinary feeding. Methionine group was fed on ordinary feeding plus 2% methionine. Intervention group was fed on ordinary feeding plus 2% methionine, as well as 0.5 mg folic acid and 25ug vitamin B12 (VitB12) by gastric perfusion every day. The rats were treated for 8 weeks. At the end of 8 weeks, absolute diet for 12h was given to the rats and subject to intraperitoneal injection with 25% urethane.5ml blood was extracted from common carotid artery and centrifuged at 3000r/min for 10 minutes. The serum was collected and stored in-20℃. We measured the concentration of Hcy,MMP-2 and MMP-3 by enzyme-linked immuno sorbent assay (ELISA), then compared these data. HE staining was performed to observe the pathology of common carotid artery.Results:(1) The levels of Hcy and MMP-2 in methionine group were 20.57±4.34μmol/L and 5470.77±102 3.11pg/ml, which were significantly higher than those in control group, P<0.001 (Hcy:11.63±4.36μmol/L and MMP-2:3227.87±746.66 pg/ml). The level of MMP-3 in methionine group was 2.91±0.46ng/ml, which was significantly higher than that in control group, P<0.05(MMP-3:2.03±0.51ng/ml).(2) The levels of Hcy,MMP-2 and MMP-3 in intervention group were 16.21±4.41μmol/L, 4030.96±848.32pg/ml and 2.460.39ng/ml respectively. The differences of the three data in interven-tion group and methionine group were statistically significant, P<0.05.(3)The proliferation of the smooth muscle cells was observed by microscope and was found that in midlayer of common carotid artery in methionine group were irregularly organized, and the elastic fiber was fusied. The common carotid artery walls in intervention group and control group were normal.Conclusion:(1) The level of Hcy in rats fed on methionine feed for 8 weeks is higher than that on ordinary feeding. Smooth muscle layer is much thicker in rats with methionine feeding than those in control group, which suggests that the model of rats with Hhcy is successful.(2) The levels of Hcy,MMP-2 and MMP-3 in rats fed on methionine feeding are were higher than those on ordinary feeding. In addition, We conclud that Hhcy can promote atherosclerosis by influencing the expression of MMP to cause the degradation of extracellular matrix and the remodelling of blood vessel wall.(3) The levels of Hcy,MMP-2 and MMP-3 in intervention group are lowerer than those in methionine group, suggesting that VitB12 and folic acid could prevent atherosclerosis by reducing the level of Hcy.