Received for publication June 6, 2005.
Revised September 19, 2005.
Accepted for publication September 21, 2005.

YC-1 Inhibits Neointima Formation in Balloon-Injured Rat Carotid Through Suppression of Expressions and Activities of MMP-2 and MMP-9

Abstract

Matrix metalloproteinases (MMPs), particularly MMP-2 and MMP-9, and post-revascularization production of vascular smooth muscle cells (VSMCs) may play key roles in development of arterial restenosis. We investigated the inhibitory effect of YC-1, a benzyl indazole compound, on MMP-2 and MMP-9 activity in a balloon-injury rat carotid artery model. Injury was induced by inserting a balloon catheter through the common carotid artery; after 14 days, histopathological analysis using immunostaining and Western blotting revealed significant restenosis with neointimal formation that was associated with enhanced protein expression of MMP-2 and MMP-9. However, these effects were dose-dependently reduced by orally administered YC-1 (1-10 mg/kg). In addition, gelatin zymography demonstrated that increased MMP-2 and MMP-9 activity was diminished by YC-1 treatment. On the other hand, YC-1 inhibited hydrolysis of the fluorogenic quenching substrate Mca-Pro-Leu-Gly-Leu-Dpa-Ala-Arg-NH₂ by recombinant MMP-2 and MMP-9 with IC₅₀ = 2.07 and 8.20 µM, respectively. RT-PCR analysis of MMP-2 and MMP-9 mRNA revealed that YC-1 significantly inhibited mRNA levels of MMPs. Finally, for the YC-1 treatment group, we did not observe elevation of cGMP levels using enzyme-linked immunosorbent assay, suggesting that YC-1 inhibition of neointimal formation is not through a cGMP-elevating pathway. These data show YC-1 suppression of neointimal formation is dependent on its influence on MMP-2 and MMP-9 protein, mRNA expression, and activity, but not through a cGMP-elevating effect. YC-1 shows therapeutic potential for treatment of restenosis after angioplasty.

Key words: YC-1, balloon-injury, cGMP-independent, matrix metalloproteinase-2, matrix metalloproteinase-9, restenosis