title: Hyperbaric oxygen preconditioning alleviates myocardial ischemic injury in rats.
abstract: It has been shown that after ischemia-reperfusion, application of hyperbaric oxygen (HBO) reduces cardiac injury. In this study we tested the hypothesis that HBO preconditioning reduces injury to the ischemic myocardium. One hundred and eight adult male Sprague-Dawley rats (250-280 g) were randomly divided into four groups: normoxia + sham surgery (CS), normoxia + permanent occlusion of the left anterior descending (LAD) coronary artery (CMI), HBO preconditioning + sham surgery (HS), and HBO preconditioning + permanent LAD occlusion (HMI). Rats receiving HBO preconditioning were intermittently exposed to 100% O(2) at 2.5 atmosphere absolute (ATA) for 60 min, twice daily for 2 days followed by 12 hrs of recovery in room air prior to the myocardial ischemic insult induced by LAD ligation. Rats in the normoxia group were time-matched with the HBO group and maintained under normoxic conditions prior to LAD occlusion. At 3 and 7 days after LAD occlusion, heart function parameters were measured by inserting a catheter into the left ventricle, infarct size was calculated using the method of TTC staining, myocardial capillary density was determined by immunohistochemical staining with a monoclonal anti-CD(31)/PECAM-1 antibody, and VEGF protein level was determined by Western blot analysis. At 3 days after LAD ligation, the infarct size of the HMI group was significantly smaller than that of the CMI group (26 +/- 2.5% vs. 38 +/- 3%, P < 0.05). The heart function parameters including left ventricular systolic pressure (LVSP), +dP/dt(max) and -dP/dt(max) were significantly improved in the HMI group compared to the CMI group at 3 and 7 days after LAD occlusion. Capillary density and VEGF protein levels were significantly increased in the ischemic myocardium pre-exposed to HBO. We conclude that HBO preconditioning alleviates myocardial ischemia in rat model.
authors.affiliation: Department of Diving Medicine, Second Military Medical University, Shanghai 200433, People's Republic of China.
authors.forename: Cuihong
authors.initials: C
authors.lastname: Han
authors.forename: Li
authors.initials: L
authors.lastname: Lin
authors.forename: Weidong
authors.initials: W
authors.lastname: Zhang
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: Shijun
authors.initials: S
authors.lastname: Lv
authors.forename: Qiang
authors.initials: Q
authors.lastname: Sun
authors.forename: Hengyi
authors.initials: H
authors.lastname: Tao
authors.forename: John H
authors.initials: JH
authors.lastname: Zhang
authors.forename: Xuejun
authors.initials: X
authors.lastname: Sun
mesh_terms: D000818:Animals; D002196:Capillaries / Q000473:pathology; D006339:Heart Rate; D006931:Hyperbaric Oxygenation; D008297:Male; D009203:Myocardial Infarction / Q000473:pathology / Q000628:therapy*; D051381:Rats; D017207:Rats, Sprague-Dawley; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D042461:Vascular Endothelial Growth Factor A; C467498:vascular endothelial growth factor A, rat