Systemic Melatonin Improves Regeneration After Facial Nerve Crush Injury in a Rat Model

Area of Science:

• Neuroscience
• Regenerative Medicine

Background:

• Facial nerve injuries pose significant management challenges.
• Melatonin is recognized for its neuroregenerative properties.

Purpose of the Study:

• To evaluate the efficacy of systemic melatonin in promoting nerve regeneration following facial nerve crush injury.
• To quantify the regenerative potential of melatonin in an animal model.

Main Methods:

• A double-blind, randomized, controlled study involving 24 rats with facial nerve crush injury.
• Three groups received either 5 mg/kg/day melatonin, 20 mg/kg/day melatonin, or a carrier solution (control) via intraperitoneal injection for 28 days.
• Primary outcomes included histomorphometric analysis (axonal and Schwann cell density) and secondary outcomes involved facial nerve activity assessed by EMG and functional tests.

Main Results:

• Histomorphometric analysis showed significantly higher mean axonal density in both melatonin treatment groups (5 mg/kg and 20 mg/kg) compared to the control group.
• Electromyography (EMG) revealed increased amplitude and decreased duration in melatonin-treated groups, indicating improved nerve activity.
• Functional assessments demonstrated statistically significant improvements in whisking amplitude in both melatonin treatment groups compared to controls.

Conclusions:

• Supraphysiological doses of systemic melatonin enhance nerve regeneration and functional recovery after facial nerve crush injury in an animal model.
• The study supports further investigation into the clinical application of melatonin for facial nerve regeneration.