The Study On Protective Effect Of Hyperoxia Liquid On Myocardial Ischemia Reperfusion In Rabbits

Myocardial ischemic disease is one of the severe disease thatremains a leading cause of human being's mortality and morbidity nowadays. Current development of studies have revealed that calcium overloading pathogensis of myocardidal reperfusion injury .By now, We have made progress in cure these diseases by using Ca2+ channel inhibitors and removal oxygen-derived free radicals. Because the hypoxia is a major pathogensis of incipient myocardid ischemic injury, We can supply oxygen by intravenous infusion to decrease the necrosis of ischemic myocardial tissue and improve its longevity. Using myocardial heart ischemic/ reperfusion model, observing the change of oxygen-derived free radicals, biochemical index and myocardial ultrastructure, we investigate the protective effect of hyperoxic liquid on myocardial ischemic/reperfusion injury. This study aimed to provide a new way for therapy of myocardial ischemic disease. Methods Groups 12 rabbits were divided randomly two groups:( I ) Control group (n=6): ligate the left anterior coronary descending branch for 40 mm and I Oml/kg balanced salt solution (BSS) was reperfused for 40 mm after removing the ligation. 1/3 and 2/3 dosage of BSS was perfttsed intravenously before ligation and before reperfusion. (11) Hyporoxic liquid group (n=6): Reperfused with hyperoxic liquid instead of NaCI and the other procedures were the same with Control group. 36 rabbits were randomly divided into three groups: (A) Control group: Coronary was only exposed but not ligated for 90mm. (B) Routine group: Ligation of left anterior coronary descending branch for 60 mm and reperfusion with lOmlIkg 0.9% NaCI for 90 mm. 1/3 and 2/3 dosage of NaC1 was perfused intravenously before ligation and before reperfusion. (C): Hyperoxic liquid group: Reperfused with hyperoxic liquid instead of NaC1 and the other procedures were the same with group B. Ischemlalreperfusion injury model Rabbits were anesthesized intravenously with pentobarbital sodium (3Omg/kg).Tracheotomy intubation and left carotid intubation were carried out. Opened chest and exposed heart. Rabbit's ischemialreperfiision model was carried out by ligation of left anterior coronary descending branch and removing the ligation after 40 mm. I 0mm before ligation, 30mm after ligation and 30mm after reperfusion, 2ml blood was drawn from carotid artery to measure the amount of CPK and malonaldehyde (MDA), the activity of superoxide dismatast (T-SOD). The change of heart rate and S-T segment in electrocardiogram were observed. Rabbits were anesthetized intravenously with pentobarbital sodium (30mg/kg). Tracheotomy intubation and left carotid intubation were carried out. Rabbit's ischemia/reperfusion model was carried out by ligation / removal of left anterior coronary descending branch. The coronary sinus blood was drawn (4ml per subject) to measure the nitric oxide (NO) and endothelin (ET) levels in different groups. The ultrastructural changes of left ventricular tissue were observed by the electron microscopes. Results Hperoxic liquid could attenuate the elevated of S-T segment in electrocardiogram which was caused by myocardial ischemia and activity of CPK in myocardial ischemia reperfusion was lower than that of the control group (P<0.0l or 0.05). Hpe...