Related Experiment Videos
Peroxynitrite-induced myocardial injury is mediated through matrix metalloproteinase-2
Wenjie Wang1, Grzegorz Sawicki, Richard Schulz
1Department of Pharmacology, Cardiovascular Research Group, University of Alberta, 4-62 Heritage Medical Research Centre, Edmonton, Alberta, T6G 2S2 Canada.
Objectives:
Peroxynitrite (ONOO(-)) mediates in part both ischemia-reperfusion and pro-inflammatory cytokine-induced injury to the heart. As oxidants like ONOO(-) are known to activate matrix metalloproteinases (MMPs), we examined whether they play a role in the detrimental action of ONOO(-) in isolated perfused rat hearts.
Methods:
Hearts were isolated from Sprague-Dawley rats and perfused retrogradely with Krebs-Henseleit buffer under constant flow. Peroxynitrite (30 and 80 microM) was infused into the hearts for 15 min. The release of MMPs into the coronary effluent and level of MMPs in the myocardium were measured by gelatin zymography.
Results:
The main gelatinolytic activity in control effluent was 72-kDa corresponding to pro-MMP-2. Infusion of ONOO(-) (80 microM) for 15 min caused a vasodilatation which peaked at 5 min and then converted into vasoconstriction by 15 min. It also caused a rapid increase in the release of 72-kDa activity within 10 min and a progressive decline in cardiac mechanical function. In contrast, decomposed ONOO(-) caused no change in vascular tone, the release of 72-kDa activity or mechanical function. The MMPs inhibitor PD-166793 prevented the ONOO(-)-induced loss in myocardial mechanical function. Detoxification of ONOO(-) with glutathione prevented both the enhancement in coronary effluent 72-kDa activity and the decline in mechanical function.
Conclusions:
Acute cardiac toxicity induced by ONOO(-) is mediated by MMP-2.
Insights
Peroxynitrite (ONOO(-)) causes heart damage by activating matrix metalloproteinase-2 (MMP-2). Inhibiting MMP-2 protects the heart from ONOO(-)-induced injury, revealing MMP-2 as a key mediator in acute cardiac toxicity.
Area of Science:
- Cardiovascular Research
- Oxidative Stress Biology
- Enzymology
Background:
- Peroxynitrite (ONOO(-)) is implicated in cardiac injury from ischemia-reperfusion and inflammatory processes.
- Oxidants, including ONOO(-), are known activators of matrix metalloproteinases (MMPs).
Purpose of the Study:
- To investigate the role of matrix metalloproteinases (MMPs) in the cardiotoxic effects of peroxynitrite (ONOO(-)) in isolated perfused rat hearts.
Main Methods:
- Isolated rat hearts were perfused and infused with varying concentrations of peroxynitrite (ONOO(-)).
- Coronary effluent and myocardial tissue were analyzed for matrix metalloproteinase (MMP) activity using gelatin zymography.
- The effects of an MMP inhibitor (PD-166793) and peroxynitrite detoxification were assessed.
Main Results:
- Peroxynitrite infusion (80 microM) induced changes in vascular tone and a rapid increase in 72-kDa gelatinolytic activity, corresponding to pro-MMP-2.
- This increase in MMP activity correlated with a decline in cardiac mechanical function.
- Decomposed peroxynitrite did not affect vascular tone, MMP release, or cardiac function, while MMP inhibition or peroxynitrite detoxification preserved mechanical function.
Conclusions:
- Acute cardiac toxicity induced by peroxynitrite (ONOO(-)) is significantly mediated by matrix metalloproteinase-2 (MMP-2).
- Targeting MMP-2 may offer a therapeutic strategy against peroxynitrite-mediated cardiac damage.