Thioctic Acid Prevents Oxidativedamage in Isolated Cardiac Myocytes
Thioctic acid and its reduced form, dihydrolipoic acid, may protect myocardium against ischemia-reperfusion damage. It is unknown whether or not thioctic acid exerts its protective action by any direct effect on heart muscle cells. The in vitro study reported here aimed to investigate the effect of thioctic acid against oxidative damage in singlet oxygen-challenged isolated cardiac myocytes. Cardiac myocytes were isolated from adult rat hearts by collagenase perfusion. Singlet oxygen was generated by photoexcitation of rose bengal (0.1 μM). Exposure to singlet oxygen induced irreversible hypercongracture in 70% to 80% of rod-shaped cardiomyocytes accompanied by a significant increase in the production of thiobarbituric acid reactive substances as an indicator for lipid peroxidation. Pretreatment of the cardiomyocytes with thioctic acid (1 mM) significantly increased the number of surviving cardiomyocytes afier exposure to singlet oxygen to 52.6% ± 9.6% vs. 22.2% ± 6.3% (p < 0.5) and reduced the amount of thiobarbituric acid reactive substances to 385 ± 42 vs. 635 ± 90 nmol/g protein (p < 0.5). The data suggest a cardoprotective effect of thioctic acid, which is possibly due to its antioxidative action.
KeywordsSinglet Oxygen Cardiac Myocytes Membrane Fluidity Thiobarbituric Acid Reactive Substance Lipoic Acid
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