Objective In this study ,we investigated the apoptosis of hair cell in the cochlea of age -related hearing loss(AHL) generated by ENU mutagenesis ,and to study a pan caspase inhibitor (z-VAD -FMK) which is to protect the cochlea hair cells from hearing loss induced by age-related hearing loss(AHL) .Methods Through z-VAD-FMK intraperitoneal injection and round window membrane (RWM) drug were delivered into the Cdh23 nmf308 nmf/nmf mice 5(postnatal days 2 -32) inner ear .ResuIts The results showed that the nmf308 mice with progressive hair cell loss along a base to apex gradient with age-related hearing loss .The cochlear OHCs reduced from 5% ~10% at 1 month to 100% at 3 month in the basal region .Substantial amounts of TUNEL -positive OHCs nuclei appeared at 1 month age ,and activated caspase-3 labeling demonstrated that most OHCs appeared at 2 months age .These suggested that DNA single strand break was attributed primarily to apoptosis of cochlear le_sions ,whereas in the later stage of lesion ,the expansion led to activation of caspase-3 activity reduced with further progression of nuclear condensation in age-related hearing loss .ConcIusion The addition of a pan caspase inhibitor (z -VAD -FMK ) significantly protected the cochlea against the hair cell loss induced by apoptosis .Our study showed that aspase inhibitor ,Z-VAD-FMK appeared to play a prominent role in age-related hearing loss media_ted hair cell death loss induced by apoptosis .Our study showed that aspase inhibitor ,Z-VAD -FMK appeared to play a prominent role in age-related hearing loss mediated hair cell death .

Objective To construct a gene recombinant lentiviral vector pCMV -G -U6 -hHGF and detect its expression in C2C12 myoblast cells .Methods hHGF gene fragments were obtained and purified by RT -PCR method ,and were cloned to pCMV -G&NR -U6 ,then the restructured lentiviral vector was transformed into e . coli DH5 alpha ,the positive colonies were identified by BamHI and Hind Ⅲ enzyme digestion .The selected positive colonies were tested by PCR and sequencing analysis .The expression plasmids and packing plasmids were co -trans_fected into 293 T cells ,and virus titer was observed under the fluorescence microscope .Furthermore ,transfected C2C12 cells with lenti virus ,and the expression of HGF was detected by PCR and WB methods .ResuIts PCR and sequencing analysis showed that the lentiviral vector was constructed correctly and successfully ,the virus titer was above 1 x 109 IU/mL .The results of PCR and WB showed that HGF expression level in the lentiviral vector group was much higher than those of in blank control and negative control groups ,and yet the expression was stable after 72 hours .ConcIusion The lentiviral vector pCMV -G﹠NR -U6 -hHGF has been successfully constructed ,and stable expressed in C2C12 cells .It provides references for experimental study in the fields of the denervated skeletal muscle fibrosis and nerve regeneration treatment .