[COX-2 or nNOS mediates cardioprotection during the final stage of the late phase of ischemic preconditioning].
The aim of the present studies was to investigate the cardioprotection of late IP at 72 h and determine the involvement of iNOS, nNOS and COX-2 in this protection. Conscious rabbits were preconditioned with three cycles of 5-minute coronary occlusion/5-minute reperfusion. The myocardial infarct area in the rabbits preconditioned 72 h earlier was significantly smaller than that in control rabbits. The activity of lactate dehydrogenase (LDH) and the level of 6-Keto-PGF1alpha in the rabbits preconditioned 72 h earlier were lower than those in control rabbits. The left ventricular systolic pressure (LVSP) and maximal velocity of contraction and relaxation (+/- dP/dtmax) were improved in rabbits preconditioned 72 h earlier. The nNOS-selective inhibitors N-propyl-L-arginine and selective cyclooxygenase-2 (COX-2) inhibitor celecoxib completely blocked the protection of late IP at 72 h, whereas the iNOS selective inhibitor S-methybisothiourea had no effect. In conclusion, the cardioprotection observed in the final stage of late IP (72 hours) is mediated by nNOS or COX-2, but not by iNOS.
Xu
Qing
Q
Basic Medical Experimental Center, Jinhua Vocational and Technological College, Jinhua 321000, China.
Tang
Bie
B
Zhang
Ning
N
Song
Lihua
L
Zhang
Zhiqin
Z
Chen
Yingying
Y
D000818:Animals; D051546:Cyclooxygenase 2 / Q000378:metabolism* / Q000502:physiology; D019157:Ischemic Preconditioning, Myocardial; D008297:Male; D009203:Myocardial Infarction / Q000201:enzymology / Q000473:pathology / Q000517:prevention & control*; D015428:Myocardial Reperfusion Injury / Q000201:enzymology / Q000378:metabolism / Q000517:prevention & control*; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism* / Q000502:physiology; D011817:Rabbits; D011897:Random Allocation; D013997:Time Factors
D052248:Nitric Oxide Synthase Type I; D051546:Cyclooxygenase 2