The Role Of TFB1M And TFB2M In The Inner Ear Of Mimetic Aging Rat Induced By D-galactose

Objective: To explore the role of the mitochondrial transcription factor B1and B2in theinner ear of mimetic aging rat induced by D-galactoseMethods:162SD rats at the age of three weeks were obtained from the experimentalanimal center of TongJi Medical College. After one week adaptive feeding,121-month-oldSD rats were used as the basal control of various biochemical assays of this experimentalstudy, the other rats were randomly divided into two groups: D-gal group (n=75) andnormal saline group(n=75). The D-gal group was treated subcutaneously with500mg/kgD-galactose daily for8weeks, but the normal saline groups were given the same volume ofnormal saline at the same schedule. Then both of the two groups were divided into5agesubgroups [3months old(just finished the injection),6months old,9months old,12monthsold,15months old]. The mRNA and western expression level of TFB1M, TFB2M, COX3and the copy number of mtDNA in inner ear were respectively detected by the Real-timequantitative PCR and Western blot assays.Results: At the corresponding point in time, the difference of mRNA and proteinexpression level of TFB1M in inner ear was not statistically significant between the D-galgroup and the control group (P>0.05). The mRNA and protein expression level of TFB2Min inner ear of D-gal group were significantly up-regulated compared with the control, andexhibited an increase with age. Both the mRNA and protein of COX3in D-gal group weredown-regulated compared with control, and the mRNA expression level of COX3wasdecreased with age. The copy number of mtDNA in D-gal group was significantlyup-regulated compared to the control group. Trends of the copy number of mtDNA in thetwo groups were first increased with age and then gradually decreased with age.Conclusion: The TFB2M may be involved in the aging process in the inner ear of themimetic aging rat induced by D-galactose. The mtDNA copy number is associated with body tissues, and changed with age and the energy demand of the cell in inner ear. TheCOX3was significantly decreased in the inner ear induced by D-galactose.