PROTECTIVE ACTION OF HYDROXYETHYL RUTOSIDES ON SINGLET OXYGEN CHALLENGED CARDIOMYOCYTES

1 The effect of a standardized mixture of beta-hydroxyethyl rutosides against oxidative damage in singlet oxygen-challenged isolated cardiac myocytes from adult rats was investigated. The morphology of the myoc ytes was evaluated as an indicator for cell viability (elongated, rod shaped cells vs. hypercontracted, rounded cells). The determination of the production of thiobarbituric acid reactive substances served as a n indicator for lipid peroxidation. 2 Exposure to singlet oxygen which was generated by photo-excitation of rose bengal (10(-7) M) reduced t he number of rod shaped (vital) cardiomyocytes by 78.5 +/- 2.5% and in creased the production of thiobarbituric acid reactive substances by 1 180 +/- 150% in comparison to incubation with control buffer. 3 Coincu bation of the cells with beta-hydroxyethyl rutosides (concentration ra nge: 6.7 pg ml(-1) to 670 mu g ml(-1)) increased the number of rod sha ped cardiomyocytes after exposure to singlet oxygen in a dose-dependen t bell-shaped manner. A significant protective effect was observed at beta-hydroxyethyl rutosides concentrations ranging from 0.67 ng ml(-1) to 67 ng ml(-1). 4 In spite of their protective action, beta-hydroxye thyl rutosides did not reduce the accumulation of thiobarbituric acid reactive substances, used as an indicator for lipid peroxidation. 5 Th e data suggest that beta-hydroxyethyl rutosides exert a protective act ion against oxygen radical-induced damage of cardiac myocytes at very low concentrations without interfering with lipid peroxidation.