RESUMEN
Ozone is a powerful oxidant that presents dual activity: either as a therapeutic or as a toxic agent. The aim of this study was to investigate the effects of intraperitoneal (i.p.) application of ozone on the endogenous antioxidant enzymes of Wistar rats compared with the amendment of the total antioxidant capacity in blood and urine. Rats were divided randomly into two groups: the control group (CG) which was injected with placebo (NaCl 0.9%) and the ozone group (OG) which was administrated daily for 10 consecutive days with ozone at a concentration of 6.3μg/Kg body weight. Blood and urine samples were collected at the beginning, after the administration period and 22 days after the initiation of the experiment. Intraperitoneal application of ozone leads to a potent Increase to glutathione peroxidase (GPx) levels with no effect to Superoxide dismutase (SOD) levels. Total antioxidant capacity (TAC) was significantly decreased in plasma, red blood cells (RBCs) and urine of the rats. Malondialdehyde (MDA) concentration in urine remained stable. To our knowledge these are the first experimental results showing that repeated i.p. application of ozone in low doses produce severe changes to the whole antioxidant capacity of the blood and indications of toxicity, as the organism exert efforts to adapt to oxidative stress.