Experimental observations on the physiology of hearing and cochlea morphology in Smad5 knockout mice / 解放军医学杂志

ABSTRACT

Objective To observe the Smad5 gene knockout and induced-changes of auditory physiology and cochlea morphology in mouse, to explore whether Smad5 gene is a new gene related to hearing function. Methods Double blind control methods were used to detect the auditory threshold of auditory brainstem responses (ABR) in the mouse of Smad5 (+/+) to Smad5(+/-) and the cochlea morphology (cochlea paraffin-cut section and basal membrane spreading section). The hair cell count was also taken. Results As shown by ABR audiometry, the average hearing of Smad5 (+/-) mouse (aged 24 weeks) is 90.63?17.65 dB (SPL) and that of Smad5(+/+) mouse is 63?19.94 dB(SPL), which are of significant difference (P0.05). Conclusion Smad5(+/-) gene knockout can cause the mouse a auditory threshold decline in moderate or severe extent. Cochlea morphology indicated that hair cells (mainly outer hair cells) in mouse cochlea basal membrane became deficient. A mechanism of Smad5 gene knockout to caused the deafness and the deficiency of hair cells remained to be further studied.