IGF-I and end-to-side nerve repair: a dose-response study.

Area of Science:

• Neuroscience
• Regenerative Medicine
• Surgical Innovation

Background:

• End-to-side nerve repair enables targeted muscle reinnervation while preserving donor nerve function.
• Insulin-like growth factor-I (IGF-I) promotes axon regeneration in injured peripheral nerves.

Purpose of the Study:

• To investigate the efficacy of local insulin-like growth factor-I (IGF-I) administration in a rat model of end-to-side nerve repair.
• To assess IGF-I's impact on functional recovery and nerve regeneration following end-to-side neurorrhaphy.

Main Methods:

• End-to-side neurorrhaphy was performed on the musculocutaneous nerve to the median nerve in Sprague-Dawley rats with induced biceps paralysis.
• Animals received local infusions of either 100 µg/ml IGF-I, 50 µg/ml IGF-I, or a vehicle control via mini-osmotic pumps.
• Functional recovery was evaluated through behavioral assessments, and nerve regeneration was analyzed via histology (axon counts, myelin thickness).

Main Results:

• Both IGF-I treated groups showed significantly improved functional recovery compared to the control group starting at 3 weeks post-surgery.
• Histological analysis at 28 days revealed significantly higher axon counts and myelin thickness/axon diameter ratios in IGF-I treated nerves.
• No significant differences were observed in motor endplate counts or between the two IGF-I dosage groups.

Conclusions:

• Local administration of IGF-I accelerates functional recovery in end-to-side nerve repairs.
• IGF-I enhances axon regeneration and nerve fiber maturation, leading to improved muscle reinnervation.
• This study supports IGF-I as a potential therapeutic agent for improving outcomes in peripheral nerve reconstructive surgery.