Korean J Physiol Pharmacol.
1999 Dec;3(6):631-640.
Enhancement of cyclosporine-induced oxidative damage of kidney
mitochondria by iron
- Affiliations
-
- 1Department of Pharmacology, College of Medicine, Chung-Ang University, Seoul, Korea.
Abstract
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The present study investigated the stimulatory effects of iron (or
ascorbate) on cyclosporine-induced kidney mitochondrial damage.
Damaging effect of 50 muM cyclosporine plus 20 muM Fe2+ on
mitochondrial lipids and proteins of rat kidney and hyaluronic acid was
greater than the summation of oxidizing action of each compound alone,
except sulfhydryl oxidation. Cyclosporine and 100 muM ascorbate showed
an enhanced damaging effect on lipids but not on proteins. The
peroxidative action of cyclosporine on lipids was enhanced with
increasing concentrations of Fe2+. Ferric ion (20 muM) also interacted
with cyclosporine to stimulate lipid peroxidation. Damaging action of
cyclosporine on mitochondrial lipids was enhanced by ascorbate (100 muM
and 1 mM). Iron chelators, DTPA and EDTA, attenuated carbonyl formation
induced by cyclosporine plus ascorbate. Cyclosporine (100 muM) and 50
muM Fe2+ (or 100 muM ascorbate) synergistically stimulated degradation
of 2- alpha deoxyribose. Cyclosporine (1 to 100 muM) reduced ferric ion
in a dose dependent manner, which is much less than ascorbate action.
Addition of Fe2+ caused a change in absorbance spectrum of cyclosporine
in 230~350 nm of wavelengths. The results show that cyclosporine
plus iron (or ascorbate) exerts an enhanced damaging effect on kidney
mitochondria. Iron and ascorbate appear to promote the nephrotoxicity
induced by cyclosporine.