To investigate the effects of knocking out the Sperm associated antigen6 (Spag6) gene on the auditory system of mice, the heterozygous type Spag6 knockout mouse model built in the previous period was used for mating and breeding, and homozygous type Spag6 gene knockout mouse (Spag
/
), heterozygous type Spag6 gene knockout mouse (Spag+/
) and wild type mouse (Spag+/+) were obtained. PCR technology was used to verify mouse models with different genotypes. After verification, the hearing threshold responses of Spag+/+ and Spag
/
genotype mice were detected. The localization of Spag6 gene in the basal membrane of the cochlea of the inner ear was detected by immunofluorescence staining. The changes of middle ear tissues were observed by H.E. staining sections. The relative expression of Prestin gene and Pgrn gene in different age mice was detected by fluorescence quantitative PCR. The relative expression of Prestin gene was detected by western blot. The results showed that Spag
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mice had hearing impairment compared with Spag+/+ mice. And Spag6 protein is distributed in different genotypes of mouse hair cells; Spag
/
mice showed otitis media. The expression of Prestin mRNA and protein in Spag
/
mice was significantly higher than that in Spag+/+ mice (P < 0.01). The expression of Pgrn gene in Spag+/+ mice was significantly higher than that in Spag
/
mice (P < 0.05). It indicates that the loss of Spag6 gene would lead to the decline of hearing sense in mice. It is likely that the Spag6 gene could affect hearing by regulating the expression of Prestin gene. And the absence of the Spag6 gene causes otitis media in mice. The results of this study can lay a theoretical foundation for the follow-up studies of Spag6 gene in deafness diseases.

Introduction

Deafness has the highest incidence of diseases with sensory or functional defects in humans, and there are many factors causing deafness, and the causes are also very complex (Godinho et al., 2017). Otitis media is a disease that occurs frequently in children. Severe otitis media can lead to permanent neurological deafness. But overall, deafness is caused by both genetic and environmental factors, with genetic factors accounting for the main cause. At present, hundreds of genes have been found to be closely related to the occurrence and development of deafness (Hoberman et al., 2017). In mammals, the perception of sound is that the external sound enters the inner ear after passing through the external auditory canal and middle ear canal. The vibration of hair bundles on the surface of hair cells and the basement membrane transforms the sound signal into electrical signal, and finally transmits it to the brain for sound perception. Hair cells are very important auditory related cells, which can quickly regulate their own morphology and respond to sound stimulation, and this response mechanism originates from a gene specifically expressed in the lateral wall of outer hair cells (Guevar et al., 2018).