Protective effects of the Compound Healthy Ear Agent against presbycusis in C57BL/6J mice

XUAN Weijun; DING Dalian; JIANG Haiyan; YANG Kun; WEI Yulong; CHEN Zhuang; TANG Junbo

doi:10.3969/j.issn.1672-2922.2016.02.029

Abstract：Objective To investigate the efficacy of the Compound Healthy Ear Agent (CHEA), a traditional Chi-nese medicine compound product, on age-related cochlear hair cell damage by two different administration methods. Methods Twenty two 1 month old C57BL/6J mice were divided into 4 groups to drink tap water until 3 months of age (young control group, n=4), drink tap water until 7 months of age (presbycusis control group, n=6), voluntarily drink CHEA until 7 months of age (n=6), or voluntarily drink CHEA until 4 months of age, followed by CHEA feeing until 7 months of age (n=6). At the end of the experiment, the cochlear basilar membrane was micro-dissected out, trimmed and mounted in glycerin on glass slides as flat surface preparations. The number of cochlear hair cells along the entire length of cochlea was counted for cochleograms. The hair cells density at two different locations of interval lesions was statistically analyzed and compared among the four groups. Results Cochlear hair cells in the young control group showed missing cells only at the end of the basal turn. Hair cell missing in the presbycusis control group extended from the basal turn to about 40%from the apex. In both CHEA treated groups, the extent and degree of missing hair cells were less compared to the presbycusis control group (P<0.001). Conclusion The traditional Chinese medicine com-pound product CHEA appears to mitigate the development age-related cochlear hair cells damage, with similar results for both administration methods tested in this study. The mechanisms may involve improving microcirculation, eliminat-ing reactive oxygen species and protecting mitochondria.