Allantoin, a Purine Metabolite, Enhances Peripheral Nerve Regeneration Following Sciatic Nerve Injury in Rats: A Stereological and Immunohistochemical Study

Abstract

Aim: Following peripheral nerve injury, in addition to axonal and myelin degeneration, a sharp increase is observed in cell numbers, especially Schwann cells, in the distal part of the injury. This study investigated the effect of allantoin, involved in purine catabolism, on the reactions occurring in the lesion area. Material and Method: An experimental sciatic nerve injury model was established with the application of pressure at 50 Newtons for 5 s to the right sciatic nerves of experimental animals following visualization with the help of pliers. Allantoin was administered to the test groups via the intraperitoneal (i.p.) route (10 mg/kg), at the same time every day for 30 days. The animals were sacrificed at the end of 30 days, following electromyography and Sciatic Function Index tests. Myelinated/unmyelinated axon numbers were evaluated stereologically. Myelin sheath thickness, axon diameter, mitotic activity, and functional improvement in muscles in this peripheral nerve degeneration model were investigated. The test results were then subjected to statistical analysis. Results: Allantoin was observed to exhibit curative effects in terms of function, although stereological tests revealed no morphological differences. Conclusion: The i.p. administration of allantoin may have a beneficial effect on nerve healing.