Endogenous antioxidants in isolated hypertrophied cardiac myocytes and hypoxia-reoxygenation injury.
Effects of hypoxia-reoxygenation (H-R) on myocytes isolated from 10 week hypertrophied and sham control rat hearts were studied. Myocyte hypertrophy was indicated by an increase in cell size. Superoxide dismutase (SOD) and glutathione peroxidase (GSHPx) enzyme activities were significantly higher and lipid peroxidation (TBARS) was lower in hypertrophied myocytes prior to any H-R. Hypertrophied myocyte population showed significantly less damage to cell morphology due to H-R. In sham as well as hypertrophied myocytes, Na+ and Ca2+ contents were increased by H-R, but Ca2+ accumulation was significantly less in the hypertrophied myocytes. Both SOD and GSHPx activities were depressed by the oxidative stress in the sham myocytes whereas these activities were not significantly changed in the hypertrophied myocytes. Catalase activity in the prehypoxic sham and hypertrophied myocytes was comparable and this activity did not change during H-R. There was a significant increase in lipid peroxidation due to H-R but this change was less in hypertrophied myocytes. This study shows less vulnerability of hypertrophied myocytes to oxidative stress and an increase in endogenous antioxidant reserve may have an important role in mediating this protection.
Kirshenbaum
L A
LA
Division of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, Winnipeg, Canada.
Hill
M
M
Singal
P K
PK
D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D001835:Body Weight; D002118:Calcium / Q000378:metabolism; D006332:Cardiomegaly / Q000378:metabolism* / Q000503:physiopathology; D002374:Catalase / Q000378:metabolism; D015687:Cell Hypoxia; D005979:Glutathione Peroxidase / Q000378:metabolism; D006339:Heart Rate; D066298:In Vitro Techniques; D015227:Lipid Peroxidation; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D009929:Organ Size; D010100:Oxygen; D011506:Proteins / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values; D012964:Sodium / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis; D016277:Ventricular Function, Left
D000975:Antioxidants; D011506:Proteins; D017392:Thiobarbituric Acid Reactive Substances; D012964:Sodium; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D010100:Oxygen; D002118:Calcium