A Study Of Ultrasound-guided Nerve-growth-factor Injection For Regeneration Of Injured Peripheral Nerve In Rabbits

ObjectiveTo inject nerve growth factor (NGF) guided by high-frequency ultrasound(HFUS) and intramuscular respectively for treating peripheral nerve injury at different time and then evaluate the effect of treatment in order to search for the suitable time and reasonable methods of using NGF.MethodsThe sciatic nerve crush injury model was established and identified by Toluidine Blue (TB) dyeing and then 60 New Zealand White Rabbits (NZW) were divided into 6 groups equally and randomly including the control group with false operation(CG), the model control group with nerve injury and no special treatment(MCG),the group treated with NGF of intramuscular injection (2μg/kg, q.24h)immediately(I-IM),the group treated with NGF of intramuscular injection (2μg/kg, q.24h) in 14 days after nerve injury (14-IM), the group treated with NGF guided by HFUS(2μg/kg, q.24h)immediately (Ⅰ-HFU) and the group treated with NGF guided by HFUS (2μg/kg, q.24h) in 14 days after nerve injury (14-HFU).After sciatic nerve injury 2w,4w,6w and 8w,physical examination, neurological score including the toe spreading reflex scale and the modified Tarlov score, ultrasonic testing, electromyogram(EMG), neuro-pathology and myopathology were used to evaluate NGF effect on the repair of peripheral nerve crush injury.ResultsTB dyeing showed that the animal model was established successfully. In general, as for the general examination, the physical and psychological state was much better for the groups treated with NGF immediately,especially for I-HFU. For the average neurological score, the score of I-HFU was highest while it is lowest for MCG among the groups. With the extension of the treating-time, the score was higher. For ultrasonic testing, we compared the continuity of the linear echo,the extent of the echo of the interruption zone,the track of nerve and the inner diameter,we found these indicators of I-HFU were the best. For the quantitative analysis of the inner diameter, I-HFU recovered the best. With the extension of treating time, the inner diameter was the most thickest in 2 weeks and gradually restored normally in 8 weeks.Similarly,electromyogram(EMG), neuro-pathology and myopathology indicated that the recovery of nerve crush injury in I-HFU was better than other groups, while it was the worst in MCG. The recovery of nerve crush injury in the groups treated with NGF immediately was better than that in the groups treated with NGF after 14 days, while14-HFU was better than 14-IM.ConclusionWhen the injury of peripheral nerve in rabbits occurred, the application of NGF in early phase is better than the application of NGF in late phase for the restoration of the function of nerve and muscle.To inject NGF guided by HFUS is better than to inject NGF intramuscular for treating peripheral nerve injury in rabbits.