Long-term Hyperbaric Oxygen Treatment Enhances Nerve Regeneration and Remyelination in a Rat Sciatic Nerve Graft Model.

BACKGROUND

Peripheral nerve injuries often lead to inconsistent outcomes due to the complexity of nerve regeneration. Hyperbaric oxygen therapy (HBOT) has been proposed to enhance regeneration by improving oxygenation, promoting angiogenesis, and facilitating cellular repair processes. This study evaluated the effects of long-term HBOT on axonal regeneration, remyelination, and functional recovery in a rat model of sciatic nerve injury repaired with autologous nerve grafts.

METHODS

Forty-two adult male Wistar rats were divided into control (surgery only) and treatment (surgery plus HBOT) groups. HBOT (2 atmospheres absolute, 100% oxygen, 1 h/d, 5 d/wk) was administered for 8 weeks. Functional recovery was assessed using the sciatic functional index, whereas regeneration was evaluated with electrophysiological tests, histological analysis, and immunohistochemistry at postoperative days (PODs) 14, 35, and 90.

RESULTS

HBOT enhanced axonal regeneration and remyelination in the middle and distal segments of the graft by POD 35. Motor neuron preservation was significantly higher in the treatment group, approaching levels of uninjured nerves by POD 90. Electrophysiological analyses revealed earlier and more consistent reinnervation in the HBOT group, with improved normalized compound muscle action potential amplitudes at POD 60. However, functional recovery assessed by the sciatic functional index showed no significant differences between groups, likely due to autotomy and the lack of physiotherapy.

CONCLUSIONS

Long-term HBOT accelerates axonal regeneration and remyelination in a rat model of peripheral nerve injury and grafting. These findings suggest that HBOT is a promising adjunctive therapy for complex nerve injuries, with potential clinical applications in reconstructive nerve surgery.