Expression Of XIAP And Caspase-3 In Primary Auditory Cortex (AI) Of C57BL/6J Mice With Age-Related Hearing Impairment

ObjectivePresbycusis, or age-related hearing loss, is the cumulative effect of aging on hearing. Also known as presbycusis, it is defined as a progressive bilateral symmetrical age-related sensorineural hearing loss. The hearing loss is most marked at higher frequency. The clinical research demonstrate presbycusis possibly was the result of the peripheral auditory system and the center auditory system function reduces the decay jointly, the hearing physiology research promptly center's change participated in presbycusis development. Along with research thorough, discovered the presbycusis with the Apoptosis of hearing cell concerns. The cell presbycusis is a highly coordinated process, in which cysteinyl aspartate specific proteinase-3 (Caspase-3) was considered is road which must be taken in this process, is the key enzyme in the cell Apoptosis, Apoptosis in the cell in the molecular machine network to occupy the core status. But Inhibitor of apoptosis protein (IAP) is the mammal in vivo only apoptosis the inhibiting factor, IAP through suppresses Caspase and many other kinds of ways to display anti-Apoptosis the function. Among them, the structure of X-linked inhibitor of apoptosis protein (XIAP) is most typical, the function is strongest, is most comprehensive. This experiment is for the purpose of through the determination XIAP,Caspase-3,Apoptosis in Primary auditory cortex of age relevant hearing decrease mouse, discusses the relation between presbycusis with Apoptosis of cell in Primary auditory cortex and relations between Apoptosis of cell in Primary auditory cortex with XIAP,CASPASE-3, knew thoroughly the pathogenesis of presbycusis, and provides the new mentality for the presbycusis treatment.Materials and methods1. separately selects 15 in February age C57BL/6J mouse (15-20 gram) and 15 in October age C57BL/6J mouse (50-60 gram), examines two group of C57BL/6J mice to Auditory brainstem response(ABR).2. useing the immunohistochemical method to check out the expression of XIAP,CASPASE-3 in two group Primary auditory cortex of C57BL/6J mice.3. useing Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling(TUNEL) dye technical and Transmission electron microscope (TEM) technology to examines the condition of apoptosis in two group of experimental animals in Primary auditory cortex.Results1. in February age group mouse, ABR examines 2KHz, the 4KHz hearing threshold value the results respectively be 64.33±8.63dB SPL, 58.33±8.80dB SPL, in October age group mouse, ABR examines the same frequency hearing threshold value, the result respectively be 76.33±7.89dB SPL, 74.67±5.16dB SPL, in October age group compares in February age group hearing threshold value to have the enhancement. At the same time in February age group mouse, ABR examines 8KHz, 16KHz, the 32KHz hearing threshold value, the result is average for 17.33±4.95dB SPL, 25.67±7.28dB SPL, 36.33±7.67dB SPL, in October age group mouse, ABR examines the same frequency hearing threshold value, the result is average for 68.00±9.78dB SPL, 52.67±7.53dB SPL, 80.33±6.11dB SPL. Two group of hearing threshold values all have the obvious difference in various frequencies (P<0.05).2. in February age group the XIAP expression number to be more weakly, after the image analysis system counting, in February age group,the XIAP expression number for 476.33±57.35, in October age group,the XIAP expression number for 402.00±23.75, both comparison has statistics significance (P<0.01). In February age group, obviously Caspase-3 expression number slightly few, after the image analysis system counting, in February age group,the Caspase-3 expression number for 856.67±62.60, in October age group the Caspase-3 expression number for 937.13±81.01, both comparison has statistics significance (P<0.01)3. compares with October age group C57BL/6J mouse, in February age group C57BL/6J mouse,the number of the cell apoptosis in the Primary auditory cortex obviously weakly. After the image analysis system counting, in February age group,the number of the cell apoptosis in the Primary auditory cortex is for 997.60±66.62, in October age group,the number of the cell apoptosis in the Primary auditory cortex is for 1978.13±101.76, both comparison has statistics significance (P<0.01).Conclusions1. the C57BL/6J mouse's hearing decrease along with the age, simultaneously the number of the cell apoptosis in the Primary auditory cortex of the C57BL/6J mouse increase obviously, the cell apoptosis in the Primary auditory cortex possibly is an important attribute.2. in the C57BL/6J mouse along with the age-related hearing impairment, the Caspase -3 expression obviously to increase, the XIAP expression reduction in the Primary auditory cortex. the expression of XIAP and Caspase-3 possibly in the presbycusis occurrence, the developing process the vital role, they possibly participated in the regulative process of the cell apoptosis in the Primary auditory cortex of the mouse.