Choudhury, SoumenSingh, Pawan Kumar2020-12-232020-12-232019-03-06https://krishikosh.egranth.ac.in/handle/1/5810157151Study on the effect of oleic acid in isoprenaline -induced myocardial injury in ratsThe present study was designed to assess the cardio-protective role of oleic acid in myocardial injury. Myocardial injury was induced in rats by intra-peritoneal injection of isoprenaline (ISO; 110 mg/kg b.wt) for two consecutive days at 24 h interval. Oleic acid was administered orally (@ 5mg/kg b.wt or 10 mg/kg b.wt) for 21 days before inducing myocardial injury to evaluate its ameliorative potential. Sample (blood, heart) were collected from different groups of experimental animals 24h after last injection of isoprenaline. Besides evaluation of heart weight to body weight (HW/BW) ratio, myocardial infarct size, oxidative stress parameters and haemato-bichemical parameters, cardio-specific biomarkers of injury, ECG, isolated right atrial response and mRNA expression of gene coding for cardiac uncoupling protein-2 (UCP-2) were quantified. Isoprenaline administration significantly increased the HW/BW ratio, myocardial infarct size, lipid profiles (total cholesterol, HDL-C, triglyceride) in ISO-induced myocardial injured rats. Further, ISO-induced myocardial injury significantly elevated the cardio-specific biomarkers (viz. LDH, CK-MB, cardiac troponin-I) suggesting the myocardial necrosis and alteration of membrane permeability. Necrosis and degeneration of cardiac myofibrils with deposition of collagen fibers were also observed in the histopathological examination of cardiac tissue sections. Further, significant increase in the heart rate and height of ST segment whereas decrease in RR and QT intervals were observed in the ISO-induced myocardial injured rats implying the abnormality in the cardiac functionality in rats following isoprenaline administration. Oleic acid pre-exposure at higher dose significantly improved the HW/BW ratio, myocardial infarct size, lipid profiles and cardiac injury biomarkers suggesting its cardio-protective role. The ameliorative potential of higher dose of oleic acid was further substantiated by its ability to reduce the cardiac oxidative stress as evidenced by significant decrease in lipid peroxidation with corresponding increase in superoxide dismutase and reduced glutathione. Significant increase in RR interval and QT intervals in oleic acid pre-exposed rats were also observed. The mRNA expression of cardiac UCP-2 gene was significantly increased in the oleic acid pre-exposed group as observed in ISO-induced myocardial injured rats. Though UCP-2 gene is responsible for fatty acid oxidation, its potential role in modulating reactive oxygen species (ROS) is also mentioned. Thus increasing the gene expression of UCP-2 in cardiac tissue may be a protective measure against myocardial injury. Further, reduction of fatty acid oxidation is always not successful in heart failure because it may directly influence the supply of ATP to comprised heart resulting in further decrease in cardiac efficiency. Thus as an alternative measure up-regulation of glucose oxidation may be a useful measure in cardiac ischemia. Further studies are warranted to evaluate the effect of oleic acid on cardiac glucose oxidation. Based on the above findings it may be inferred that oleic acid has the potential cardioprotective action against myocardial injury due to its anti-oxidative property and its ability to modulate cardiac metabolic processes. Thus incorporation of oleic acid as a component of diet may be a useful measure against myocardial ischemia or injury.EnglishThesis