[Effects of exogenous brain-derived neurotrophic factor on the morphology and function of cochlea in the animal model of hereditary hearing loss].

Objective: To study the effect of early administration exogenous BDNF on the morphology and function of conditional knockout Cx26 mice cochlea. Method: Conditional knockout Cx26 mice was chosen as animal model, early after birth (P0-P2) exogenous BDNF (rAAV mediated BDNF plasmid, AAV-BDNF) was injected through scala media. Expression of BDNF in the cochlea was observed by western-blot, the growth promoting effect of nerve fibers was detected by IHC; 2 m after injection, the protective effect of BDNF on corti and spiral ganglion cells were detected by resin section; animal hearing were tested by ABR. Result: ①Exogenous BDNF could be well expressed in the inner ear; ②Exogenous BDNF has a good effect on the growth of cochlea nerve fiber; ③Exogenous BDNF could protect the morphology of organ of corti; to count the number of spiral ganglion cells, using the density value of top-turn in non-injected ear as the standard unit, the values of middle and basal turn in injected ear were 0.81±0.02, 0.65±0.02, compared with non-injected ears, both statistically significant difference could be found, indicates that exogenous BDNF can effectively improve the number of spiral ganglion cells. ④By calculating the ABR threshold of different frequencies of the injected and non-injected ear, there was no statistical difference between them. Indicates that exogenous BDNF has no effect on improving the function of cochlea. Conclusion: The protective effect of early administration exogenous BDNF was effective in the cochlea and spiral ganglion cells of conditional knockout Cx26 mice, but no protective effect for auditory function.
Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose.
(Copyright© by the Editorial Department of Journal of Clinical Otorhinolaryngology Head and Neck Surgery.)