The effects of glial growth factor, nerve growth factor, N acetyl cysteine and methylprednisolone on nerve healing in the traumatic facial nerve paralysis: an experimental animal study

2.ABSTRACT THE EFFECTS OF GLIAL GROWTH FACTOR, NERVE GROWTH FACTOR, N ACETYL CYSTEINE AND METHYLPREDNISOLONE ON NERVE HEALING IN THE TRAUMATIC FACIAL NERVE PARALYSIS: AN EXPERIMENTAL ANIMAL STUDY The aim of this study was to evaluate the effects of treatment with glial growth factor, nerve growth factor, N acetyl cysteine and methylprednisolone on nerve regeneration of nerve anastomosis in the traumatic facial nerve paralysis. 50 female New Zelland rabbits weighing between 2500-3000 gram were used for this study. All of the rabbits divided to 5 groups randomly and the same surgically procedure was applied to all animals. Group 1 (control group): No treatment was given. Group 2 (Nerve growth factor group): 250 ng/O.lml nerve growth factor was given to anastomosis side. Group 3 (Glial growth factor): 500 ng/O.lml glial growth factor was given to anastomosis side. Group 4 (N acetyl cysteine): 50 mg/kg/day N-acetyl cysteine was given intramuscullary. Group 5 (Methylprednisolone): 1 mg/kg/day Methylprednisolone was given intramuscullary. Growth factors were injected to epineurium of the anastomosis region and the same doses were repeated subcutanly to the anastomosis side after 24 and 48 hours. Methylprednisolone and N-acetyl cysteine were injected intramuscullary once a day during 2 months. Buccal branch of the facial nerve was identified on the left side of the rabbit face. 2 milimeter segment of buccal branch of facial nerve was removed and free tips of nerve were anastomosed with 9-0 monofilaman prolyn. Anastomosis regions were removed after 2 months and researched by electrone microscopy. The best nerve regeneration was determined in glial growth factor group and worthless regeneration was determined in methylprednisolone group when compared to control group. Proliferation of glial and Schwann cells were seen in glial growthfactor group According to regeneration amount, Nerve growth factor group and N- acetyl cysteine groups were following the glial growth factor group respectively. Axonal regression and meaningful mithocondrial cristaliasis in myelinised nerve fibers were seen in group 5 and there was no siginificant regeneration in group 5. It was determeined that numbers of myelin debris (findings of worthless regeneration) were decreased in glial growth factor group whether increased in methylprednisolone group (p<0.005). In conclusion, in traumatic facial paralysis of rabbits, the roles of glial growth factor, nerve growth factor and N acetyl cysteine on increasing the nerve regeneration is notably. New studies in humans are needed for using these factors in the treatment of traumatic facial paralysis. Key words: Traumatic facial palsy, NGF, GGF, Methylprednisolone, N acetyl cysteine 4