Protective effect of adenoviral-mediated brain derived neurotrophic factor gene on spiral ganglion

Objective To observe the expression of brain derived neurotrophic factor (BDNF) in the cochlea of guinea pig, and assess the activity of BDNF in spiral ganglion cell following the damage of noise Methods Twenty seven guinea pigs were exposed to a 4 kHz narrow band noise at 135 dB SPL for 4 hours At seven days after the noise exposure, twelve guinea pigs were inoculated with ad BDNF, and twelve guinea pigs were inoculated with ad LacZ, while three guinea pigs were inoculated with artificial perilymphatic fluid The animals were sacrificed After 1 week, 4 weeks and 8weeks, respectively The cochlea was stained with immunohistochemisty (ABC method) to examine the expression of BDNF The number of spiral ganglion cell was counted to assess the activity of BDNF Results BDNF gene was expressed in whole cochlea, and the expression was obviously elevated 1 week after the adenovirus administration and reduced thereafter The number of degenerated cells in ad BDNF group in the eight weeks was lower than that in another two groups and the different between them was statistical significant ( P 0 01) Conclusion Adenoviral mediated brain derived neurotrophic factor can be expressed in a high level in the cochlea of guinea pig, and may prevent the cell of spiral ganglion from the damage of noise This study lays the groundwork for alleviation of hearing loss using gene therapy