Introduction: Dexamethasone and vitamin B₁₂ are currently used in the clinic to treat peripheral nerve damage but their mechanisms of action remain incompletely understood. In this study we hypothesized that dexamethasone and vitamin B₁₂ promote the production of endogenous neurotrophic factors, thereby enhancing peripheral nerve repair.
Material and methods: Ninety-six adult male Wistar rats were employed to establish a sciatic nerve injury model. They were then randomly divided into 4 groups to be subjected to different treatment: saline (group A), dexamethasone (group B), vitamin B₁₂ (group C), and dexamethasone combined with vitamin B₁₂ (group D). The walking behavior of rats was evaluated by footprint analysis, and the nerve regeneration was assessed by electrophysiological analysis and ultrastructural examination. The expression of brain-derived neurotrophic factor (BDNF), glial cell-derived neurotrophic factor, NT-3 and IL-6 in the injured sciatic nerves was detected by immunohistochemical and RT-PCR analysis.
Results: Dexamethasone and vitamin B₁₂ promoted the regeneration of myelinated nerve fibers and the proliferation of Schwann cells. Furthermore, dexamethasone and vitamin B₁₂ promoted the recovery of sciatic functional index and sensory nerve conduction velocity, and upregulated BDNF expression in the injured sciatic nerves.
Conclusions: Dexamethasone and vitamin B₁₂ promote peripheral nerve repair in a rat model of sciatic nerve injury through the upregulation of BDNF expression. These findings provide new insight into the neurotrophic effects of dexamethasone and vitamin B₁₂ and support the application of these agents in clinical treatment of peripheral nerve injury.