Effect of Isoproterenol on LDL Susceptibility to Oxidation and Serum Total Antioxidant Capacity in Cyclosporine-Treated Rats

Background: Cyclosporine therapy is associated with a variety of adverse effects. Recent studies have suggested increased oxidative stress as a cause of these side effects. Objective: Since, melatonin is one of the most powerful known antioxidants, and considering that isoproterenol is one of the drugs stimulating endogenous melatonin production, we tried to determine the effect of isoproterenol on LDL susceptibility to oxidation and serum total antioxidant capacity in cyclosporinetreated rats. Methods: 32 male Wistar rats were divided into four groups: group A were controls that received placebo; group B received intraperitoneal isoproterenol (20 mg/kg/d) alone; group C received intravenous cyclosporine (15 mg/kg/d) alone; and group D received both drugs simultaneously at the same doses and durations- cyclosporine one week after administration of isoproterenol. Blood samples were drawn four times from rats in each group: before injections, during the treatment, end of the treatment, and one week after the last injections. Results: There was a significant (p<0.05) increase in LDL susceptibility to oxidation, and a decrease in serum total antioxidant capacity (p<0.05) in group C rats. But, there were no significant changes in group B and D rats in terms of LDL susceptibility to oxidation and total antioxidant capacity. Conclusion: Isoproterenol may be capable of delaying adverse effects of cyclosporine by preventing the increase in LDL susceptibility to oxidation, and decrease in serum total antioxidant capacity.