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Hepatotoxic effect of cyclosporin A in the mitochondrial respiratory chain
Author(s) -
Rodríguez Lilia Cristina De la Cruz,
Araujo Carmen Rosa,
Posleman Sara Emilia,
Rey María del Rosario
Publication year - 2007
Publication title -
journal of applied toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.784
H-Index - 87
eISSN - 1099-1263
pISSN - 0260-437X
DOI - 10.1002/jat.1192
Subject(s) - succinate dehydrogenase , glutamate dehydrogenase , respiratory chain , chemistry , enzyme , mitochondrion , oxidase test , respiratory system , pharmacology , substrate (aquarium) , dehydrogenase , biochemistry , medicine , biology , glutamate receptor , receptor , ecology
Abstract Cyclosporin A (CyA), a potent immunosuppressant, was used to determine the hepatotoxic effect in long‐term treatments. Male Wistar rats were used in these experiments. They were given CyA chronically at doses used in patients for 120 days, and at doses of 5, 10, 15 and 20 mg kg −1 day −1 . These doses amount to CyA values in blood of 200 ± 24, 314 ± 40, 445 ± 33 and 598 ± 53 ng ml −1 , respectively. A significant increase in glutamate dehydrogenase (GLDH) was found in the groups treated with 15 and 20 mg kg −1 day −1 , which would point to mitochondria as the potential target of the toxic action of CyA. The mitochondrial respiratory chain of rat livers was studied in enzyme complexes I and II. Enzyme complex I was determined by spectrophotometry at 340 nm using NADH oxidase with the respirable substrate 10 m m NADH; enzyme complex II was determined by monitoring succinate dehydrogenase by oxymetry using the respirable substrate 10 m m succinate. The results show the inhibition of NADH oxidase in the groups treated with 10, 15 and 20 mg kg −1 day −1 , an effect dependent both on time and on CyA concentration. Enzyme complex II showed a decrease in oxygen consumption. These findings were confirmed by histological studies (hematoxylin‐eosin technique). Conclusions: Long‐term treatment with CyA at doses of 15 and 20 mg kg −1 day −1 , amounting to concentrations in blood of 445 ± 33 and 598 ± 53 ng ml −1 , causes alterations in the mitochondria, revealed by the increase in serum GLDH and by the functional alteration of enzyme complexes I and II of the mitochondrial respiratory chain. Copyright © 2007 John Wiley & Sons, Ltd.