Trimetazidine improves post-ischemic recovery by preserving endothelial nitric oxide synthase expression in isolated working rat hearts.
OBJECTIVE
Previous investigations have consistently shown that the piperazine derivative trimetazidine (TMZ, 1-[2,3,4-trimethoxybenzil] piperazine, dihydrocloride) has cardioprotective effects in the experimental ischemia-reperfusion model. We tested the hypothesis that cardioprotective effect of TMZ is partly mediated by preservation of the endothelial barrier of the coronary microcirculation.


METHODS
Isolated Wistar rat (250-300 g) hearts were subjected to a 15 min period of global ischemia and 180 min reperfusion in the presence or absence of 1 microM TMZ. Hemodynamic parameters, heart weight, creatinekinase (CK) release and microvascular permeability (FITC-albumin extravasation) were evaluated. In addition, eNOS gene expression was estimated by rt-PCR, and eNOS protein levels were assessed by Western analysis. In order to confirm the involvement of NO in mediating the cardioprotective effects of TMZ, 30 microM N(omega)-nitro-l-arginine methylester (L-NAME), a specific inhibitor of nitric oxide synthase, was used.


RESULTS
After ischemia and reperfusion, TMZ produced a significant improvement of mechanical function associated with a reduction of CK release and FITC-albumin diffusion (P<0.001); the agent also resulted in improvement in coronary flow (at 45 min+27% vs control). The eNOS mRNA and protein levels were significantly higher in TMZ-treated hearts compared to controls. The addition of L-NAME significantly reduced the beneficial effects of TMZ on contractile function, CK release and FITC-albumin diffusion.


CONCLUSIONS
in the isolated rat heart, TMZ exerts a relevant, NO-dependent, cardioprotection against ischemia-reperfusion injury and preserves the endothelial barrier of the coronary circulation. This could contribute to explain the cardioprotective action of TMZ following ischemia and reperfusion.
Di Napoli
Pericle
P
Laboratory of Experimental Cardiology, Department of Clinical Science and Bioimaging, Biology Section, University of Chieti, Chieti, Italy. dinapoli@unich.it <dinapoli@unich.it>
Chierchia
Sergio
S
Taccardi
Alfonso Antonio
AA
Grilli
Alfredo
A
Felaco
Mario
M
De Caterina
Raffaele
R
Barsotti
Antonio
A
D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002199:Capillary Permeability / Q000187:drug effects; D017931:DNA Primers; D006321:Heart / Q000187:drug effects*; D008297:Male; D009206:Myocardium / Q000201:enzymology*; D052250:Nitric Oxide Synthase Type III / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D015427:Reperfusion Injury; D014292:Trimetazidine / Q000494:pharmacology*
D017931:DNA Primers; D012333:RNA, Messenger; D052250:Nitric Oxide Synthase Type III; D014292:Trimetazidine