The Expression And Regulation Of Connexin26 And Connexin30 In The Inner Ear Of Mimetic Aging Rat Induced By D-galactose

Objective: The aim of the present study are to clarify the relationship between the aberrant methylation of connexin26 gene promoter and the age-related hearing loss.Method:Injection of D-galactose is a useful method for establishing an animal model of mimetic aging.Auditory brainstem response (ABR) was used to detect the hearing threshold of rats before and after the treatment.The frequency of mtDNA4834bp deletion were detected using real-time PCR. The mRNA and protein level of Cx26 were detected by real-time RT-PCR technique and western blot technique respectively. We carried out a detailed methylation analysis of the Cx26 promoter by bisulfite sequencing analysis(BSP). The correlation analysis was used to research the relationship between the hypermethylation of Cx26 promoter and its mRNA, protein expression .Results:The data showed that the frequency of the 4834bp deletion increase with the dose of D-galactose.The difference in ABR threshold shift among all groups were not significant(P>0.05). The difference of mRNA level of Cx26 between the four groups was also not significant(P>0.05).Cx26 protein levels in D group were significantly higher than A and B group,the difference was statistically significant(P<0.05), but it was not significant between the other groups(P>0.05). Methyl Primer Express software displayed the promoter site of Cx26 gene showed abundant CpG islands. Bisulfite sequencing analysis (BSP) showed the hypermethylation status of Cx26 promoter in high dose group. The hypermethylation levels were associated with Cx26 gene expressions.Conclusions: The hypermethylation of Cx26 promoter in experiment groups relates to its low expression, which speculates that the methylation of aging may be involved in the development of presbycusis. Objective: To explore the expression of connexin30 in the inner ear of mimetic aging rat induced by D-galactose.Method:Injection of D-galactose is a useful method for establishing an animal model of mimetic aging.Auditory brainstem response (ABR) was used to detect the hearing threshold of rats before and after the treatment.The frequency of mtDNA4834bp deletion were detected using real-time PCR. The mRNA and protein level of Cx30 were detected by real-time RT-PCR technique and western blot technique respectively.Results:The data showed that the frequency of the 4834bp deletion increase with the dose of D-galactose.The difference in ABR threshold shift among all groups were not significant(P>0.05). The difference of mRNA level of Cx30 between the four groups was also not significant(P>0.05). Cx30 protein levels in B group were significantly higher than A and D group,the difference was statistically significant(P<0.05),but it was not significant between the other groups(P>0.05).Conclusions: The protein levels of Cx30 increased in experiment groups, which speculates that may be involved in the development of presbycusis.