R. Castillo, O.S. León, N. Merino1, S. Menéndez2, S. Sam, L. Pérez, E. Cruz.
Center for Research and Biological Evaluation. Pharmacy and Food Institute, Havana University, Cuba.
1National Center for Scientific Research, Cuba.
2Ozone Research Center, Cuba.

It has been demonstrated that controlled ozone administration could be able to promote an oxidative preconditioning, preventing the hepatocellular damage mediated by free radicals. The aim of this study is to evaluate the influence of different ozone doses on the oxidative preconditioning. The oxidative challenge was carried out using carbon tetrachloride (CCl4) as an inductor of free radicals (1 mL/kg CCl4 by intraperitoneal way of a solution of 10 % CCl4 in vegetable oil). 50 adult female Sprague Dawley rats (220-250 g) were used for this study. The rats were divided in 5 experimental groups: 1, a negative control group treated only with vegetable oil by intraperitoneal route; 2, a positive control group using 1 mL/kg of 10 % CCl4 solution; 3, 4 and 5 ozone groups, were the rats were submitted, daily, to 15 ozone treatments at doses of 0.5, 1 and 2 mg O3/kg of weight, respectively, by rectal insufflation and after the last ozone treatment a challenge with CCl4. The ozone protective effect against cellular damage, induced by CCl4, was determined through different mediators of oxidative stress (Superoxide Dismutase, Catalase, Phospholipase A and Lipid Peroxidation) and histopathological studies. The results demonstrated that the mechanism of protection against de cellular damage, mediated by CCl4, were dependent of the different ozone doses used in this experimental model. The behavior of the biochemical parameters measured were dependent of the ozone doses, demonstrating their functional relationship. An ozone dependent oxide-reduction factor, which well correlates with the biochemical parameters, was found. Theoretically, an ozone minimum effective dose, equals to 1.52 mg/kg, was estimated. The histopathological results, according to lipidosis and glucogenic depletion are in correspondence with the behavior of the biochemical parameters measured and the ozone dependent oxide-reduction factor.