Nitric oxide opens the second window of protection in is chemic preconditioning via induction of heat shock protein 72 / 中国病理生理杂志

ABSTRACT

AIM: To examine the inhibition of nitric oxid e (NO) synthesis during ischemic preconditioning (IP) on the induction of heat s hock protein 72 (HSP72) and infarct size-limiting effect of the second window of protection. METHODS: Rabbits were subjected to 4 cycles of 5 min of coronary a r tery occlusion separated by 10 min reperfusion, or received a sham operation. Du ring this procedure, N G-nitro-L-arginine methyl ester (L-NAME, an inhibitor of NO synthase) was injected intravenously 5 min before IP followed by its continu ous infusion. Twenty-four hours later, the hearts were rapidly excised for assay ing HSP72 expression or were subjected to 30 min coronary artery occlusion follo wed by 120 min reperfusion and then measured infarct size (IS). RESULTS: Twenty-four hours later, immunoblotting revealed an inc rease in HSP72 protein levels in the IP group, and this was blocked by L-NAME. I S of the IP rabbits was reduced as compared with the control (29 8%?3 7% vs 50 8%?4 3%, P