Diverse effects of natural antioxidants on cyclosporin cytotoxicity in rat renal tubular cells

• Published in: Nephrology, dialysis, transplantation Vol. 20; no. 8; pp. 1551 - 1558
• Main Authors: Galletti, Patrizia, Di Gennaro, Chiara Iolanda, Migliardi, Valentina, Indaco, Stefania, Della Ragione, Fulvio, Manna, Caterina, Chiodini, Paolo, Capasso, Giovanni, Zappia, Vincenzo
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.08.2005; Oxford Publishing Limited (England)
• Subjects: Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Animals; Antioxidants - therapeutic use; Biological and medical sciences; Blood. Blood and plasma substitutes. Blood products. Blood cells. Blood typing. Plasmapheresis. Apheresis; Cell Survival - drug effects; Cells, Cultured; cyclosporin A; Cyclosporine - toxicity; Emergency and intensive care: renal failure. Dialysis management; Epithelium - drug effects; Fluoresceins; Glutathione - metabolism; hydroxytyrosol; Intensive care medicine; Kidney Diseases - chemically induced; Kidney Diseases - metabolism; Kidney Diseases - prevention & control; Kidney Tubules, Proximal - drug effects; Kidney Tubules, Proximal - metabolism; Lipid Peroxides - metabolism; Medical sciences; Nephrology. Urinary tract diseases; Nephropathies. Renovascular diseases. Renal failure; oxidative stress; Phenylethyl Alcohol - analogs & derivatives; Phenylethyl Alcohol - therapeutic use; proximal tubular cells; Rats; Rats, Inbred WKY; Reactive Oxygen Species - metabolism; Renal failure; Resveratrol; ROS; Stilbenes - therapeutic use; Thiobarbituric Acid Reactive Substances - metabolism; Transfusions. Complications. Transfusion reactions. Cell and gene therapy; vitamin E; Vitamin E - therapeutic use; Kidney disease; Oxidative stress; Urinary system disease; Rat; Hemodialysis; Rodentia; Vitamin; vitamin E; cyclosporin A; Cytotoxicity; Antioxidant; Extrarenal dialysis; Vertebrata; Mammalia; Animal; proximal tubular cells; Renal failure; Resveratrol; ROS; Ciclosporin; Immunosuppressive agent; hydroxytyrosol
• ISSN: 0931-0509; 1460-2385
• DOI: 10.1093/ndt/gfh846

Background. As is well known, the use of the immunosuppressive drug cyclosporin A (CsA) is partially restricted by its nephrotoxic effects, which include early changes in haemodynamics followed by irreversible injuries to the renal tubules. Although the mechanisms responsible for these side effects are poorly understood, an involvement of reactive oxygen species (ROS) has been suggested. In this study, we selected three natural antioxidants, resveratrol, hydroxytyrosol and vitamin E, on the basis of their scavenging capabilities, and tested their protective effects against CsA toxicity. Methods. Immortalized rat tubular cells (RPTc) were used as the model system. Cell viability was checked with trypan blue assay, and free radical formation was measured using the fluorescent probe 2,7-dichlorofluorescein (DCF). We evaluated several oxidative stress parameters, including phospholipid peroxidation products, glutathione levels and oxygenase expression. Results. Incubation of RPTc with 25 μM CsA induced a significant decrease in cell viability paralleled by intracellular ROS formation and alterations in lipid peroxidation. There was also an imbalance of glutathione redox state as well as upregulation of heme oxygenase-1 (HO-1). The three antioxidants, at micromolar concentration, quantitatively prevented the ROS-activated DCF fluorescent signal and membrane lipid peroxidation. Both hydroxytyrosol and resveratrol strengthened the CsA induction of HO-1 expression. Moreover, vitamin E and resveratrol counteracted CsA-induced changes in the glutathione redox state via different mechanisms, whereas hydroxytyrosol was completely ineffective. Similarly, CsA-dependent nephrotoxicity was prevented by vitamin E, while resveratrol only exerted partial protection, and hydroxytyrosol showed no protective effects. Conclusion. Our results indicate that the diverse cytoprotective effects of the antioxidants tested in these studies were not directly related to their scavenging capabilities. These findings confirm a key role for glutathione in protecting cells from CsA-induced adverse effects and do not support a direct link between CsA-mediated ROS generation and adverse renal effects.