Establishment of sperm associated antigen 6 gene knockout mouse model and its mechanism of deafness

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−/− 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.