Experimental study of the effect of NGF injection via different ways on the regeneration of sciatic nerve

Objective To explore the effect of nerve growth factor (NGF) injection via different ways on the regeneration of sciatic nerve.Methods Forty SD rats (2 months old) were employed in this study.After the rat was anesthetized,the left sciatic nerve was exposed and cut-off,while part of the epineurium was reserved and then sutured the epineurium.Then,the rats were divided into 4 groups:Group A:NGF at 1 μg dose was injected locally into the anastomosis the day after surgery and last for 30 days.Group B:NGF at 30μg dose was injected locally into the anastomosis the day after surgery only for one time.Group C:NGF at 1 μg dose was injected intramuscularly into the contralateral side the day after surgery and last for 30 days.Group D:Equivoluminal saline was injected locally into the anastomosis the day after surgery and last for 30 days.Eight weeks later,nerve conduction velocity and regeneration of the sciatic nerve were examined.Results Among the four groups,the nerve conduction velocity of group A is the fastest (P＜0.05),and the number of the nerve fibers was the highest.These two indicators for group B took the second place (P＜0.05).And the nerve conduction velocities of group C,D were the slowest,and the numbers of the nerve fibers of these two groups were the fewest.Conclusions NGF can promote the regeneration of sciatic nerve mainly based on the local action.Continuous low dosage is the best method of administration. Key words: Nerve growth factor;  Nerve regeneration;  Sciatic nerve