Ischemia/Reperfusion injury in the myocardium generates an inflammatory response that can potentiate damage while at the same time is necessary for healing. Myocardial tissue infiltration of neutrophils (PMN) is a hallmark of this response. PMNs in the reperfused tissue and those isolated from cardiac-specific lymph were examined immunohistochemically and were found to be positive for matrix metalloproteinase 9 (MMP 9), an enzyme involved in matrix remodeling. Gel zymography on cell free lymph revealed the presence of latent MMP 2 and MMP 9. MMP 2 levels did not change over time while MMP 9 levels increased, peaking at 3-8 h and returning to baseline by 24 h post reperfusion. In contrast, in situ zymography demonstrated a reperfusion-dependent increase in gelatinase activity within 3 h. This rise in MMP 9 was temporally and spatially concordant with the amount of PMN infiltration. We suggest that early reperfusion results in PMN infiltration and degranulation. The resultant activated MMP 9 may be a factor in the improved tissue repair seen with reperfusion.
|Original language||English (US)|
|State||Published - Mar 20 1998|
ASJC Scopus subject areas
- Molecular Biology