RESUMO
BACKGROUND: Vitamin B12 and alpha lipoic acid (ALA) are known to promote functional and morphological recovery after peripheral nerve injury. OBJECTIVE: To compare the regenerative and neuroprotective effects of vitamin B12 and ALA treatment after sciatic nerve injury. METHODS: A total of 40 rats were randomly assigned to control (sciatic nerve exposure without injury or anastomosis), sham (sciatic nerve injury and epineural anastomosis were performed but no treatment was administered), PS (isotonic saline was administered for 12 weeks after surgery), ALA (2 mg/kg ALA was administered for 12 weeks after surgery), and vitamin B12 groups (2 mg/kg cyanocobalamin was administered for 12 weeks after surgery). Functional recovery was determined by footprint analysis, in vivo neurophysiology, and ex vivo histopathological examination. RESULTS: ALA treatment produced significant improvements in sciatic functional index values and non-significant improvements on electroneuromyography compared to vitamin B12 treatment. Upon histopathological examination, the regenerative effects of ALA were relevant to axonal structural recovery whereas vitamin B12 produced greater improvements in edema and myelination. CONCLUSIONS: While both vitamin B12 and ALA produced improvements after sciatic nerve injury, ALA was more functionally effective. The unique ultrastructural effects of vitamin B12 and ALA treatment should be considered in future studies.