Paper Information

Title:  HYPEROXIA MAY PROTECT THE HEART AGAINST ISCHEMIC INJURY VIA PROXYNITRITE
Type: SPEECH
Author(s): ESMAEILI DEHAJ MANSOUR*,BAHARVAND B.,FOUAD ALDINI M.,KHOUSHBATEN A.
 
 *DEPARTMENT OF PHYSIOLOGY, SCHOOL OF MEDICINE, SHAHID SADUGH UNIVERSITY OF MEDICAL SCIENCES, YAZD, IRAN
 
Name of Seminar: IRANIAN CONGRESS OF PHYSIOLOGY AND PHARMACOLOGY
Type of Seminar:  CONGRESS
Sponsor:  PHYSIOLOGY AND PHARMACOLOGY SOCIETY, MASHHAD UNIVERSITY OF MEDICAL SCIENCE
Date:  2009Volume 19
 
 
Abstract: 

Our previous study showed that pre-exposure to hyperoxic environment (O2>95%) for 10 min could induce preconditioning in rat hearts. In the present study we wanted to know whether hyperoxia preconditioning is mediated through the production of reactive oxygen species (ROS) and proxynitrite. 49 rats were divided into 4 groups: Group 1 pre-exposed to normoxia (normal air) for 120 min, group 2 was like group 1 except the administration of N-mercaptopropionyl glycin (MPG, 100 mg/kg, ip) and group 3 and 4 were similar to group 1 and 2, respectively, with the exception of hyperoxia instead of normoxia. All animals were anesthetized 24 h later; left anterior descending coronary artery was occluded for 30 min and then reperfused for 120 min. Lead II electrocardiogram was monitored and finally infarct size was measured by triphenyltetrazolium chloride. Results showed that infarct size significantly reduced in group 2 that lost with MPG (group 4). MPG stopped antiarrhythmic effects of hyperoxia preconditioning in group 4, so that there were not different in ventricular ectopic beat, tachycardia and fibrillation incidence among group 1 and 4. Also normoxia alone and together with MPG did not have any significant effect on infarct size and arrhythmia. In conclusion, the finding of this study show that hyperoxia preconditioning might be mediated through ROS especially proxynitrite in anesthetized rats.

 
Keyword(s): PRECONDITIONING, INFARCTION, HYPEROXIA, RAT, ARRHYTHMIA
 
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