Effects of Sodium Selenite and Vitamin E on the Development of Morphine Dependency in Mice

Background: Antioxidant drugs may be useful in preventing morphine-induced dependency by suppressing oxidative stress. Vitamin E which has many essential roles in the body is a powerful antioxidant. On the other hand, selenium is an essential trace element that plays a strong role in various biochemical pathways. The aim of this study was to investigate the effects of sodium selenite and vitamin E on morphine-induced dependency in mice. Methods: Ninety male mice, weighing 20 to 30 g, were randomly divided into 10 groups and were treated as follows: a) saline and b) morphine groups were pretreated (for 2 days) with normal saline (10 ml.kg^-1.day^-1, ip) then daily doses of normal saline (10 ml.kg^-1.day^-1, ip) and morphine (50 mg.kg^-1.day^-1) were added to the injections for the following 4 days, respectively. c, d, e) sodium selenite, f, g, h) vitamin E, i) vitamin E solvent (almond oil) and j) co-administration groups were pretreated (for 2 days) with sodium selenite (0.25, 0.5, 1 mg.kg-1.day-1, ip), vitamin E (20, 40, 60 IU.kg^-1.day^-1, ip), vitamin E solvent (10 ml.kg^-1.day^-1, ip) and combination of the drugs respectively, then morphine doses (50 mg.kg^-1.day^-1, ip) were added to the injections for the following 4 days. Withdrawal symptoms were evaluated after injecting naloxone (4 mg/kg/ day). Biochemical evaluations were also performed. Results: The results showed that co-administration of sodium selenite and vitamin E (at low doses) significantly reduced morphine dependency (p 0.05). Conclusion: The synergistic effect of sodium selenite and vitamin E can be a suitable and efficient approach to reduce dependency.