Oxygen free radical damage of isolated cardiomyocytes: comparative protective effect of radical scavengers and calcium antagonists

Abstract

Oxygen free radicals have been shown to play a major role in the development of perfusion abnormalities, contractile dysfunction, and irreversible injury in ischemic-reperfused myocardium. The aim of this study was to assess the direct protective effects of radical scavengers, calcium antagonists, and combination of these substances against free radical induced myocyte damage. Viability (% of rod-shaped cells) and adenine nucleotide content (AdN, high-pressure liquid chromatography) of isolated adult rat cardiomyocytes were measured after exposure to hypoxanthine (2 mM) and xanthine oxidase (25 mU/ml). After 90 min, viability of myocytes decreased to 4.2 +/- 3.4% (mean +/- SEM) of pre-exposure control, and AdN decreased from 28.2 +/- 1.8 to 8.09 +/- 1.1 nmol/mg protein. Addition of catalase (1500 U/ml) resulted in the preservation of viability (77 +/- 6% of pre-exposure control, n = 6, mean +/- SEM), and AdN 84 +/- 6%, p less than 0.001. These values are not significantly different from those measured in myocytes not exposed to free radicals (88 +/- 9% and 79 +/- 6%, respectively). Superoxide dismutase (2400 U/ml), dimethylthiourea (10 mM), and desferrioxamine (1 mM) did not preserve either viability or AdN. The calcium antagonist verapamil (10 microM) also preserved myocyte viability significantly (23 +/- 9.7%, p less than 0.05 vs unprotected cells), but failed to prevent the loss of AdN (13.2 +/- 4%, not significant as compared to unprotected cells). Viability and AdN in myocytes treated with nifedipine (10 microM) or diltiazem (10 microM) were not higher than in unprotected cells. All combined treatment forms which included catalase resulted in the preservation of myocyte viability as well as AdN. These data show that only the hydrogen peroxide scavenger catalase protects isolated cardiomyocytes against free radicals generated in the purine catabolic pathway.

Biologically active constituents of the secretome of human W8B2+ cardiac stem cells

“…1A ) was less than the PBS vehicle control (Fig. 3D ), probably due to the presence of pleiotropic antioxidants such as ascorbic acid 19 , α-tocopherol 19 , nicotinic acid 20 and hypoxanthine 21 in the basal medium for all are cytoprotective at high concentration. Interestingly, the paracrine actions of W8B2 + CSC conditioned medium in promoting angiogenesis and cardiomyocyte proliferation were not found in cation or anion fractions of conditioned medium.…”

Studies of the Toxic Effects of Norepinephrine on Isolated Cardiomyocytes of Guinea-Pigs

“…Data represent the mean ± SEM (n = 4). phological means (% of rod-shaped cells), is impaired by adding systems generating oxygen free radicals [13]. These deleterious effects of oxygen radical generating systems can be inhibited by adding the radical scavenger catalase.…”

Lipid Peroxidation, Antioxidative Enzyme Activities, and Cytosolic Free Calcium Levels in Rat Hippocampus-Derived Cells Exposed to Free Radicals.

“…In experimental studies for free radical-induced cell death in cardiomyocytes [5,24], hepatocytes [15], and endothelial cells [7,8,10], the HX-XOD system has been widely used to generate free radicals, since the HX-XOD system is a major source of free radicals in vivo. In this study, free radical-positive cells increased with a dose-dependent manner in HV16-4 cells exposed to free radicals generated by HX-XOD system.…”