Isoflurane impairs antioxidant defence system in guinea pig kidney

Purpose: To investigate whether free radical metabolism is changed due to i soflurane treatment and, if so, to elucidate the role of changed free radic al metabolism in the nephrotoxicity. Materials and methods: Fifteen guinea pigs were used in the study. Five wer e treated with isoflurane in oxy gen, five with oxygen and five were contro ls. Animals were exposed to isoflurane and oxygen three limes. Each treatme nt was performed for 30 min once a day for three consecutive days. Activiti es of free radical enzymes, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px); values of antioxidant parameters, antioxi dant potential (AOP), non-enzymatic superoxide radical scavenger activity ( NSSA) and oxidation resistance (OR) and, level of an oxidant parameter name ly, malondialdehyde (MDA) were determined in the renal tissues of the group s. Blood was also obtained for serum creatinine and urea analyses. Results: AOP, NSSA, SOD and CAT activities were decreased; (0.0188 +/- 0.00 26 vs 0.0156 +/- 0.0015, P < 0.025; 8.72 +/- 1.80 vs 6.40 +/- 1.22, P < 0.0 5; 76.71 +/-. 18.54 vs 52.79 +/- 11.68, P < 0.025; 71.26 +/- 15.58 vs 55.39 +/- 8.83; P < 0.05, respectively) but, MDA level, OR value and GSH-Px acti vities increased (10.89 +/- 1.57 vs 15.87 +/- 2.97, P < 0.01; 0.84 +/- 0.34 vs 2.28 +/- 1.39, P < 0.05; 1.45 +/- 0.83 vs 3.45 +/- 1.20, P < 0.01, resp ectively) in kidney tissues from isoflurane-treated group compared with con trols, No differences were observed between control and oxygen groups with regard to all analysis parameters except GSH-Px. Conclusion: Isoflurane impairs the antioxidant defence system and this oxid ant stress may play a part in the isoflurane-induced renal toxicity.