Effects of homocysteine on matrix metalloproteinase-1 and tissue inhibitors of metalloproteinase-1 in vascular smooth muscle cells

Liqun REN; Jinfeng WANG; Yongmei LI; Xiuyun ZHANG; Guangsheng LI

ABSTRACT

BACKGROUND:

Homocysteine (HCY) has been verified as an independent risk factor of atherosclerosis and atherothrombosis of cardiovascular disease.

OBJECTIVE:

To observe the effects of HCY on the secretion and activity of matrix metallopotinase-1 (MMP-1) and tissue inhibitors of metalloproteinase-1 (TIMP-1) in vascular smooth muscle cells (VSMCs).

DESIGN:

Auto-control observation.

SETTING:

Pathology Room, Institute of Regeneration Medical Sciences, Jilin University.MATERIALS In vitro cultured vascular smooth muscles cells (VSMCs) of rats were obtained from male Wistar rats with the body mass of about 150 g from weeks 4-6 supplied by Laboratory of Animals, Norman Bethune Medical Sciences Division, Jilin University.

METHODS:

The experiment was performed at the Pathology Room, Institute of Regeneration Medical Sciences, Jilin University from May 2001 to May 2003. VSMCs ofin vitro cultured rats were adopted and divided into 5 groups, 0(control group), 0.10, 0.25, 0.50 and 1.00 mmol/L HCY were added, respectively for 48 hours. Effect of HCY on activity of MMP-1 was observed with zymography. The secretions of MMP-1 and TIMP-1 and their mRNA expressions were studied with Western blot and semi-quantitative reverse transcription polymerase chin (RT-PCR).MAIN OUTCOME

MEASURES:

Activity of MMP-1, secretions of MMP-1 and TIMP-1 and their mRNA expressions.

RESULTS:

①Secretions of MMP-1 and TIMP-1 The secretion of MMP-1 in the 0.25, 0.50 and 1.00 mmol/L HCY groups was lower significantly than that in the control group (P ＜ 0.05-0.01). The secretion of TIMP-1 in the 0.10, 0.25, 0.50 and 1.00 mmol/L HCY groups was higher than that in the control group (P＜ 0.05-0.01). ②The MMP-1 activity decreased with the increase of HCY, but reduced obviously in the 0.50 and 1.00 mmol/L HCY groups (P ＜ 0.01). ③The expression of MMP-1 mRNA in the 4 HCY groups was lower markedly than that in the control group (P ＜ 0.01). The expression of TIMP-1 mRNA in the 0.25 mmol/L HCY group was higher than that in the control group (P ＜ 0.05), and it was higher remarkably in the 0.50 and 1.00 mmol/L HCY groups than that in the control group (P ＜ 0.01).

CONCLUSION:

HCY can inhibit enzyme activity, decrease collagen degradation and induce collagen accumulation by inhibiting the secretion of MMP-1, which indicates that reduction of collagen degradation induced by HCY is one of the pathogenesies of atherosclerosis.