Histopathological effects of ketamine with preservative on the rat’s spinal cord

Introduction: Pain is the most prevalent clinical complaint of the patients so various methods studied for pain control such as injecting the local anesthetics opioids in sub-arachnoid space. In recent years, ketamine is used with this method. In the first considerations on animals, some cases with damages on neurons and neurotic changes were reported following intrathecal ketamine injection. Thus, it has been advised that to be performed more surveys in this field before using in man. Materials and Methods: In this study, the neurotoxicity effect of ketamine with preservative by two different doses on the spinal cord of rats was evaluated. Thirty rats selected randomly and divided into 3 groups (n=10). The first and second groups were injected with 800 and 1600 µg/kg ketamine with preservative. The third group received normal saline solution with equal volume in lumbar cistern. After a month, the rats went under anesthesia with ether, they killed and autopsy performed. Then the spinal cords were extracted and considered histopathologically. Results: Histopathological studies have shown no symptoms of nerve injury such as demyelinization and degeneration of nerve in ketamine-treated animals. Conclusion: This finding indicated that interathecal injection of ketamine with preservative had no nerve injury and would seem to be safe.