Distribution and Dynamic Changes in Matrix Metalloproteinase (MMP)-2, MMP-9, and Collagen in an In Stent Restenosis Process.

Objective The aim of this study was to observe the spatial distribution and dynamic changes of matrix metalloproteinase (MMP)-2, MMP-9, and collagen in in stent restenosis (ISR) and to explore their influence on ISR. Methods Sixty Z type stents were implanted into the common iliac arteries of minipigs, which were divided into 10 groups (six in each group) according to euthanasia time (6 hours, and 1, 3, 7, 14, 28, 56, 84, 168, and 336 days). After the samples were harvested, haematoxylin and eosin staining, immunohistochemical staining, Western blotting, and Picrosirius red staining were performed for all groups. Results ISR occurred in all six minipigs in the 56 day group (percentage diameter stenosis range 71.6%–79.2%, mean ± standard deviation 75.6% ± 2.5%). The percentage diameter stenosis decreased to 38.3% ± 2.7% at 336 days (p  Conclusion This study has demonstrated the spatial distribution of and dynamic changes in MMP-2, MMP-9, and collagen in ISR by simulating the process of neointima from generation to regression after stent implantation. When ISR occurred, MMP-2 and MMP-9 expression decreased and collagen content reached its maximum, which might contribute to ISR.