Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/206
Title: The Role of the Calcium Stores and Cyclooxygenase-2 in Pacing Postconditioning Protection of the Heart
Authors: Aseel Mubarak Khalaf 
Supervisor: Dr. Fawzi Babiker
Keywords: Ischemia;Reperfusion;Postconditioning;NGF;COX
Issue Date: 2013
Publisher:  Kuwait university - college of graduate studies
Abstract: Pacing postconditioning (PPC) protects the heart against ischemia reperfusion (I/R) injury. The role of calcium release from sarcoplasmic reticulum (SR), the recently described acidic stores and cyclooxygenase-2 (COX-2) in heart protection, requires more investigations. The aim of the present study was to characterize the effect of calcium stores (SR), and the acidic stores and COX-2 on I/R injury and PPC protection to the heart. Langendorff perfused isolated rat hearts (n=6 per group) were used for this study. Controls were subjected to 30 minutes unprotected ischemia with no further treatment. PPC protocol was 3 cycles of 30 seconds each of LV pacing alternated with 30 seconds right atrium (RA) pacing. Ischemia was produced by ligation of the left anterior descending artery. All hearts were allowed 30 min reperfusion. Heart hemodynamics was computed by a data acquisition program and the infarct size was evaluated by triphenyltetrazolium chloride (TTC) staining. ELISA was used to detect COX-2 expression level in the cardiomyocyte lysate and the coronary effluent in various experimental groups. All drugs were added at the beginning of reperfusion. Pacing postconditioning significantly (P<0.05) normalized LV hemodynamics and significantly (P<0.001) decreased the infarct size as compared to the respective control group. Blockade of SR calcium release significantly (P<0.01) recovered LV hemodynamics and reduced the infarct size (P<0.04), when used alone or in combination with PPC. Interestingly, the release of calcium from acidic stores alone or in combination with PPC significantly (P<0.03) improved LV hemodynamics and decreased the infarct size (P<0.001) as compared to the respective control group. Cyclooxygenase-2 alone or in combination with PPC significantly (P<0.01) improved the LV hemodynamics and decreased the infarct size (P<0.001) as compared to the respective control group. COX-2 expression has been significantly (P<0.01) increased by PPC and significantly (P<0.04) decreased by calcium release from SR. A positive additive effect was shown when calcium release from acidic store or blockade of calcium release from SR was combined with PPC. Calcium release from acidic stores, COX-2 and the blockade of calcium release from SR protect the heart against I/R. Synergy was noticed in combination of calcium release from acidic stores or blockade of calcium release from SR when combined with PPC.
URI: http://hdl.handle.net/123456789/206
Appears in Programs:0530 Physiology (M.Sc.)

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