Study On The Injured Mechanisms And Therapeutic Methods Of Sgn

Sensorineural hearing loss (SHL) is one of the most popular diseases which affect people's normal life quality. Many studies have been carried out on the pathogenic mechanism and therapy method of SHL. The main diseased regions locate at hair cells and primary afferent spiral ganglion neurons (SGN), which can't be regenerated after injury. Therefore, it is very important to explore the methods to repair the injured SGN and improve its self-recovery ability. Our study focuses on the stem cells therapy and H2 therapy to injured SGN. Besides, the expression of micro-RNA involved in SGN's growth, differentiation and maturation process and its effect on injured SGN recovery was explored.SHL animal models were successfully built using ouabain in our study. We found that there was a dose-dependent effect between ouabain and auditory brainstem response (ABR) threshold shift. However, there was no change in distortion product otoacoustic emissions (DPOAE). We detected the SGN's injury in vivo and in vitro by immunohistochemistry, transmission election microscopy (TEM), scanning electron microscope (SEM). That will provide insights into prevention and therapy of SHL.Two therapeutic methods were tried after SGN injury. First, E14C57BL/6-GFP bulbus olfactorius stem cells were administrated in two ways. One is through acoustic nerve roots and the other through internal carotid artery. A few stem cells was observed around the SGN. Second, H2 was administrated in the injured SGN. Auditory improvement was detected by ABR. SGN injury was found to be alleviated significantly by immunohistochemistry. It has been reported that H2 plays an protective role in oxidative damage and apoptosis. Further studies will be helpful in its protective mechanisms to neural system.We found a few stem cells around injured SGN. There may be some other factors, such as its special genetic character. During the process of stem cells'developing, it was explored whether stem cell could immigrate, proliferate, and differentiate into SGN. SGN of E14,P1,P5 and adult animals were screened by gene chip technology. We found that 17 micro RNAs were up-regulated and 19 were down-regulated. Results showed that micro RNA may participate in the development of SGN. Then 3 identified micro RNA(miR-21,miR-135a* and miR-205) were detected by real-time RT-PCR. Further studied will be performed in the future.