Regulation by reactive oxygen species of matrix metalloproteinase-1, 3 and tissue inhibitor of matrix metalloproteinase-1 in smooth muscle cells

AIM: To understand whether reactive oxygen species promote the rupture of atherosclerotic plaques by regulating the balance of matrix metalloproteinase-1, 3 (MMP-1, 3) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) in smooth muscle cells. METHODS: Aortic smooth muscle cells from 4-6months-healthy abortive fetuses were incubated for 24 hours with xanthine (100 μmol/L) and xanthine oxidase (5 U/L) in vitro . MMP-1, 3 and TIMP-1 in the concentrated culture media were measured by Western blotting ( n =3 independent experiments). RESULTS: Incubation with xanthine/xanthine oxdiase decreased the amount of MMP-1 in the aortic smooth muscle cells (21.2%±5.5% of the control group), and pro-MMP-1 was activated completely. Reactive oxygen species (ROS) also activated pro-MMP-3, and increased the production of MMP-3 in the aortic smooth muscle cells. On the other hand, ROS inhibited the production of TIMP-1 in the aortic smooth muscle cells. CONCLUSION: It is complicated that ROS regulates the balance of MMPs and TIMPs. ROS may contribute to matrix degradation and the rupture in the atherosclerotic plaques.