RESUMO
<p><b>OBJECTIVE</b>To establish a mice model of aminoglycoside antibiotics (AmAn) induced ototoxicity. Then to investigate the sensitivity of AmAn induced ototoxicity in three mouse strains and effect of kanamycin on the expression of Na-K-2Cl co-transporter-1 (NKCC1) in stria vascularis.</p><p><b>METHODS</b>C57BL/ 6J, CBA/CaJ, NKCC1 +/- mice (each of twenty-four) were randomly divided into four experimental groups A, B, C and D (A kanamycin alone, B kanamycin plus 2, 3-dihydroxybenzoate, C 2, 3-dihydroxybenzoate alone, D control group). Mice were injected with kanamycin or/and 2, 3-dihydroxybenzoate for 14 days. Auditory function was measured by auditory brainstem response (ABR) and morphology of cochlea was observed by succinate dehydrogenase staining. Expression of NKCC1 was detected by immunohistochemistry.</p><p><b>RESULTS</b>Mice in group A developed significant ABR threshold shifts (P < 0.01), which were accompanied by out hair cells loss. Mice in group B significantly attenuated ABR threshold shifts with out hair cells loss (P <0.01). The immunostaining of NKCC1 in stria vascularis was attenuated significantly in group A compared with group D (P < 0.01) while the immunostaining in group B was enhanced than which in group A (P < 0.01). CBA/CaJ mice has the highest sensitivity to AmAn in three mouse strains.</p><p><b>CONCLUSIONS</b>An mouse model of AmAn induced ototoxicity could be established by administration of kanamycin. Kanamycin could inhibit the expression of NKCC1 in stria vascularis. 2, 3-dihydroxybenzoate could attenuate AmAn induced ototoxicity maybe by enhancing the expression of NKCC1. Mice that had the characteristic of presbycusis didn't show additional sensitivity of AmAn induced ototoxicity.</p>