Changes in Antioxidant Status of Myocardium during Oxidative Stress under the Influence of Coenzyme Q₁₀

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V. L. Lakomkin^*, G. G. Konovalova, E. I. Kalenikova, I. V. Zabbarova, A. I. Kaminnyi, A. K. Tikhaze, V. Z. Lankin, E. K. Ruuge, and V. I. Kapelko

Russian Research and Productive Cardiology Complex, Ministry of Health of Russian Federation, 3-ya Cherepkovskaya ul. 15A, 121552 Moscow, Russia; fax: (7-095) 414-6699; E-mail: v.lakomkin@cardio.ru

^* To whom correspondence should be addressed.

Received April 9, 2004; Revision received June 9, 2004

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Changes in myocardium were studied during oxidative stress induced by infusion of hydrogen peroxide in the coronary vessels of isolated rat heart. Moderate concentrations of H₂O₂ increased the heart rate but decreased the contractile force, whereas higher concentrations of H₂O₂ decreased both parameters and increased the end diastolic pressure. The effect of H₂O₂ was stable, cumulative, and was associated with disturbance in respiration of mitochondria, increased production of ROS in them, and decrease in activities of antioxidant enzymes in the myocardium. Changes in the antioxidant status of the myocardium induced by long-term addition of coenzyme Q₁₀ into food was accompanied by decrease in the negative inotropic effect of H₂O₂, whereas the levels of superoxide dismutase and glutathione peroxidase after oxidative stress were virtually unchanged. The activities of these enzymes displayed a high positive correlation with the cardiac function. The findings suggest that coenzyme Q₁₀ should increase resistance of the myocardium to oxidative stress not only by a direct antioxidant mechanism but also indirectly, due to increased protection of antioxidant enzymes.

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KEY WORDS: isolated heart, antioxidant protection, oxidative stress, mitochondria, coenzyme Q₁₀, hydrogen peroxide

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