Visualization of doxorubicin-induced oxidative stress in isolated cardiac myocytes

Abstract

The paper presents high-resolution fluorescence images obtained using laser-scanning confocal microscopy. Isolated cells from adult rat hearts were preloaded with 2',7'-dichlorofluorescin (an oxidant-sensitive fluorescent probe) and exposed to doxo- rubicin, an important anticancer drug with prominent cardioxicity. Fluorescence images were collected from live cells simultaneously on two channels: 1) 515-530 nm emission range was used to monitor an increase in dichlorofluorescein, the oxidized product of dichlorofluorescein, and 2) emission > 610 nm was used to visualize the intracellular distribution of doxorubicin. The images reveal intracellular oxidation close to the mitochondria after only 20 min of exposure of isolated cardiomyocytes to 40-160 microM doxorubicin. The data confirm an oxidative mechanism of doxorubicin cardiotoxicity and demonstrate the capability of a new technique to monitor intracellular oxidation in living cardiomyocytes.

Ameliorative effect of naringin against doxorubicin-induced acute cardiac toxicity in rats

“…These ROS cause single strand scission of DNA and also alters the structural and functional integrity of cells by different mechanisms, including lipid peroxidation and proteolysis. Consequently, the oxidative damage of cellular and mitochondrial membranes and critical cellular components leads to cardiomyocyte death (Sarvazyan, 1996). Furthermore, Dox also reduces the activities of several antioxidant enzymes such as SOD and CAT resulting in the reduction in the capacity of cardiac cells to inactivate ROS (Doroshow et al, 1980).…”

Induction of premature senescence in cardiomyocytes by doxorubicin as a novel mechanism of myocardial damage

“…The compound DCFH-DA is a useful fluorescent marker of oxidative stress (Sarvazyan, 1996). The esterified form of DCFH-DA rapidly penetrates cell membranes and is deacetylated by intracellular esterases.…”

Anthracycline-induced phospholipase A2 inhibition

“…To visualize the involvement of free radicals in doxorubicin-mediated myocyte injury we used confocal laser scanning microscopy and the oxidant-sensitive fluorescent dye, 2′,7′-dichlorofluorescin. Exposure to doxorubicin produced a rapid and concentration-dependent increase in the fluorescence that appeared to occur in close proximity to the mitochondria [6,7]. We have also shown that pretreatment of the cells with dexrazoxane inhibited doxorubicin-induced increase in oxidant-sensitive fluorescence.…”

“…Therefore, the ability of cells to deal with anthracycline-enhanced lipid peroxidation is severely compromised by AIPI. It also explains how anthracyclines can lead to measurable lipid peroxidation [17], while no significant increases in free radical formation have been detected at clinically relevant doxorubicin concentrations [6,18]. Another selenium-dependent enzymemembrane-bound phospholipid hydroperoxide glutathione peroxidase (PHGPX) has been shown to reduce phospholipid hydroperoxides in situ without the necessity of prior hydrolysis by PLA 2 [19].…”