The Experimental Study On Axoplasmic Transportation Rehabilitation Effects By Continuous Abdominal Administration With Nerve Growth Factor (NGF) In Injured Peripheral Nerves

Objective: To investigated the effect of continuous abdominal administration of nerve growth factor (NGF) on post-injury rehabilitation of axoplasmic transport function of peripheral nerve after bridging the nerve ends by establishing nerve regeneration chamber, in the method of biotin dextran amine(BDA) nerve tracing.Methods: 26 adult Sprague-Dawley rats were randomly divided into 3 groups: 12 rats in Group A as experimental group, 12 rats in Group B as control group, and 2 rats in Group C as normal group. In Group A and Group B, 3mm defect in sciatic nerves of both sides were maded by surgically cutting off the nerves, and the gap between the two ends was bridged using a silicone tube, to form a nerve regeneration chamber. In the operation, 0.04ml (40Au) NGF and physiological saline of equal quantity was injected respectively. Each side had half, quantity. In Group C, this surgical treatment was not carried out. Following the surgery, 40 Au NGF and physiological saline of equal quantity was injected into the abdomen, respectively, and the ulceration and its healing on the feet was recorded. In the 2nd, 4th, 6th, and 8th weeks post-surgery, the sciatic nerves were exposed, ligated with 4# silk suture at 5mm distal to the bridging site, and slowly injected 1uL 10% BAD with a microsyringe that was linked to a micro glass-tube at 5mm proximal to the bridging site. The rats were anesthesia again 18h later and sacrificed by perfusion through the ascending aorta. The samples were fixed and segmented in the sucrose solution to the bottom. The nerve samples at the bridging site and at 3mm proximal to the ligation site were surgically removed. In Group C, the sciatic nerves of both sides were exposed, ligated with 4# silk suture at 18mm distal to the sciatic tuberodties site, and slowly injected 1uL 10% BAD with a microsyringe at 5mm distal to the sciatic tuberodties site. 18h later, 5mm nerve samples proximal to the ligation site were got in the way of group A and B.Nerve samples were frozen sectioned, and pathological sections were HE stained and nerve tracing stained. The regeneration of nerves post-injury and the rehabilitation of its axoplasmic transport function were analysed.Results: The ulceration on the feet was not so severe, with fewer loss of toes, and was healing more quickly in experimental group than in controls in the 2nd, 4th, 6th, and 8th weeks post-surgery. No neuroma was observed in both groups. Compared with the controls, blood supply around the nerve regeneration chamber was more abundant, with less adhesions anf less swelling in the experimental group. The regenerated nerve was more thick, smooth, elastic and had better connection with the distal ends. The HE staining showed coincident findings (P<0.05) between 2 groups. The BDA tracing staining showed no positive in controls until in the 8th week, whereas it began to showed positive nerves at bridging site since the 6th week and at distal nerve since the 8th week in the experimental group with more positive nerve fibers, bigger diameters and deeper staining (P<0.05).Conclusion:â‘ Continuous abdominal administration of nerve growth factor (NGF) can facilitate the post-injury peripheral nerves regeneration, and enhances the rehabilitation of axoplasmic transport function of the injured peripheral nerve.â‘¡BDA nerve tracing is an effective method of axoplasmic transport observation.