Inhibiting matrix metalloproteinase-2 reduces protein release into coronary effluent from isolated rat hearts during ischemia-reperfusion.
BACKGROUND
Previous studies have shown that the disruption of the coronary endothelium and the increase in its permeability during ischemia-reperfusion (I/R), are linked to matrix metalloproteinase-2 (MMP-2) activity. Studies from our group have shown that during I/R, activity of MMP-2 in the coronary effluent increases and this increase is associated with cardiac dysfunction, which in turn, can be prevented by MMP inhibitors. Therefore, we hypothesize that inhibiting MMPs reduces the MMP-2 dependent disruption of the coronary endothelium and subsequent protein release during I/R.


METHODS
Isolated rat hearts were perfused in the Langendorff mode at a constant pressure and subjected to 15, 20 or 30 min no-flow ischemia followed by 30 min of reperfusion. The MMP inhibitors, o-phenanthroline (Phen, 100 microM) or doxycycline (Doxy, 30 microM) an inhibitors of MMPs, were added to the perfusion solution 10 min before ischemia and for the first 10 min of reperfusion. The coronary effluents were collected during perfusion for protein analysis. Creatine kinase was measured as an index of cellular damage. Endothelial integrity was assessed by measuring coronary flow and by measuring the levels of serotransferrin and interstitial albumin in the coronary effluent. Additionally, damage to the endothelium was assessed histologically by light microscopy analysis of the cellular structure of the myocardium. MMP-2 activity was measured by zymography in hearts subjected to 15, 20 and 30 min of ischemia without reperfusion.


RESULTS
MMP-2 activity was increased in heart tissue at the end of ischemia and was correlated with duration of ischemia. The post-ischemia decrease in coronary flow, and the increase in the release of serotransferrin and albumin were attenuated by Phen. Edema (another indirect marker of endothelial damage) was observed in I/R heart and the edema was abolished in I/R heart treated with MMP inhibitors.


CONCLUSIONS
MMP inhibition not only reduces cardiac mechanical dysfunction but also reduces endothelial damage resulting from cardiac I/R injury.
Dept. of Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, S7N 5E5, Canada.
Justyna
J
Fert-Bober
Hernando
H
Leon
Jolanta
J
Sawicka
Rashpal S
RS
Basran
Richard M
RM
Devon
Richard
R
Schulz
Grzegorz
G
Sawicki
D000818:Animals; D003326:Coronary Circulation; D004487:Edema / Q000517:prevention & control; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D061965:Matrix Metalloproteinase Inhibitors; D015428:Myocardial Reperfusion Injury / Q000188:drug therapy* / Q000378:metabolism*; D009206:Myocardium / Q000201:enzymology; D010618:Phenanthrolines / Q000494:pharmacology*; D040901:Proteomics; D051381:Rats; D017207:Rats, Sprague-Dawley
D004791:Enzyme Inhibitors; D061965:Matrix Metalloproteinase Inhibitors; D010618:Phenanthrolines; D020778:Matrix Metalloproteinase 2