Abstract
Delayed reperfusion has a beneficial effect on prognosis, independent of infarct size. One potential mechanism to explain this observation may be an effect on infarct healing. In this study, the impact of delayed reperfusion on two aspects of the healing process was examined, the activity of matrix metalloproteinase (MMP) enzymes and the expression of fibronectin (FN) mRNA. The rat model of coronary artery ligation was used and rats were randomly assigned to delayed reperfusion (150 min following coronary ligation) or permanent ligation. Animals were subsequently killed 1, 2, 3 and 7 days following infarction. Infarct tissue was harvested for MMP activity (zymography), FN mRNA (RNase protection analysis) and protein (immunofluorescence microscopy and Western analysis), and collagen content (hydroxyproline concentration). Infarction produced marked activation of MMP-1, -2, and -9. Reperfusion significantly attenuated the activity of these enzymes (50% reduction in MMP-1,P=0.03 and 60% reduction in MMP-2 at 7 days,P=0.001; 55% reduction in MMP-9 at 24 h and 84% reduction at 48 h,P=0.01 and 0.002, respectively). Delayed reperfusion also produced a trend toward a greater increase in FN mRNA 24 h following infarction and immunofluorescent staining suggested the presence of more FN protein at this point. These data demonstrate that delayed reperfusion alters matrix metalloproteinase activity and fibronectin mRNA expression in the infarct zone. The impact of these changes on infarct healing and their association with the improved prognosis of a patent infarct vessel following infarction will require further study.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.