Preliminary Experimental Study On The Facial Nerve Regeneration In Silicone Chamber: The Influence Of Hepatocyte Growth Factor

Objective: Hepatocyte growth factor (HGF) exhibits properties on different types of neurons, including motor, sensory and parasympathetic neurons. Facial nerve (FN) injury is a common disease in practice medicine, successful microsurgery technic and microenviroment are equally essential for peripheral nerve regeneration .In order to select an effective and convenient neurotrophin which can promote nerve regeneration in clinical aspect , Our study is to establish the FN transected model, in which the superior buccal division of FN of adult New Zealand rabbit was transected and a nerve growth chamber created to elucidate the role of HGF in the regeneration of facial nerve injury. Methods: The bilateral superior buccal branches of facial nerve were exposed and transected, a nerve growth chamber were created by suturing the epineurium and silicone chamber under microscope .The chambers of experimental sides(right sides of facial nerve) were injected with HGF/normal saline and that of the control sides with normal saline of same amount (10μL ) ,the regenerated nerves in the chambers were dissected and postoperative evaluation were performed byelectrophyiological testing , histopathologic, morphological studies under gross observation, light microscope at 1,2,4 weeks after operation, respectively. Results: At 1 week after operation, there was no significant difference between the experimental and the control sides. At 2 week, the velocity of nerve conduction of FN didn't appear, but the degree of degeneration in experimental sides were worse than of the control sides. At 4 week, the velocity of nerve conduction in experimental sides was faster than that of control sides, and the CMAP incubation period of experimental sides was shorter than that of the control sides; Light microscope (LM) observation of experimental sides showed superior value than that of controls. The average diameter of regenerative nerve were 1.99±0.33μm and the acreage were 3.29±0.79μm2 in experimental sides and 1.53±0.42μm,2.01±1.28μm2 in control sides ,the average number of myelinated axons were1679±1699 in experimental side and 364±179 in the control side respectively. There was significant difference between the experimental and the control sides (p<0.05). Conclusion: HGF within a silicone chamber enhanced FN regeneration in New Zealand rabbits in a short period. The long-term effect and recovery of metabolism of HGF need more experiment.