The Efficacy of New Neuronal Growth Factor in the Healing of the Sciatic Nerves in Rabbits

BACKGROUND AND OBJECTIVE: Regeneration of nervous tissue is unpredictable and an ideal growth factor to influence the healing of the injured nerves is not available. A recent study in rats had shown that a new neuronal growth factor (NNGF) was effective in the early healing of the sciatic nerves. The aim of this experimental study is to test the efficacy of NNGF in the healing of iatrogenic division of the sciatic nerves in a larger animal (rabbits). METHODS: White New Zealand 20 male rabbits of 6 months of age were divided into two groups. Intramuscular ketamine and xylazine were used to anesthetize the animals. The sciatic nerves were divided using scalpel blade 15 and 10/0 Vicryl was used to repair the divided neural tissue. In the study group, 10 mg/kg body weight of NNGF was instilled on the top of the divided nerves and the wound was closed. At 4 weeks, the operated limbs were observed for any trophic skin changes. Nerve conduction studies were carried out using train-of-four-Watch SX, Organon (Ireland) Ltd., and Ireland. The rabbits were put to death humanely and the sciatic nerves were removed and delivered to the pathologist in 2% formalin. The pathologists were blinded about the two groups. RESULTS: Electromyographic study done at 4 weeks showed in the untreated group; the mean twitches 1-T4 was 0.45 ± 0.31% and in the treated group, the average was 77.912 ± 5% (P > 0.001). Microscopic anatomy in the treated group revealed prominent healing by regeneration was evidenced by showing growth of its proximal segments into an empty endoneurial tube which was not seen in the control group. In the control group, the nerves showed no histological element of healing by regeneration. CONCLUSIONS: NNGF proves that in a larger animal at 4 weeks profoundly influenced early regeneration of experimentally created divisions of myelinated nerve tissue.