Coenzyme Q10 Modulates Apoptotic Effects of Chronic Administration of Methadone on NMRI Mouse Hippocampus

OBJECTIVE: Methadone is one of the widely used drug substances prescribed in treatment of opioid dependence and pain management; however, several studies have shown its neurotoxic effects on individuals and animal models. The purpose of this study was to assess neuroprotective effects of Coenzyme Q10 (CoQ10) on neurotoxicity induced by methadone in hippocampus of adult NMRI male mice. MATERIALS AND METHODS: In this experimental study, 48 adult NMRI male mice were randomly divided into 4 groups (n=12 in each) including Methadone, Methadone with sesame oil, Methadone with CoQ10 and saline. The injections of methadone, saline and sesame oil were performed intraperitoneally for 20 days. 24 hours after last injection, half of the animals in each group (n=6) were randomly assessed for evaluating of spatial memory by radial maze. Following behavioral study, animals were sacrificed, and their brains were removed to evaluate pyknotic cells through histological assessment. The remaining were used to study the expression of Arc, Bax, Bcl-2 and Bdnf genes. RESULTS: Results of the present study showed that daily administration of methadone increased the number of pyknotic neurons in the CA1 hippocampus and altered the expression of Bax, Bdnf, Arc and Bcl-2. However, it did not alter spatial memory comparing to saline group. CoQ10 treatment significantly reduced the number of pyknotic cells and expression of Bax, Bdnf, Arc when compared to the vehicle group treated by sesame oil. However, the expression of Bcl-2 significantly increased as a result of CoQ10 treatment. CONCLUSION: CoQ10 reduced the neuronal damage caused by methadone in the hippocampus CA1.