Aminoglycoside ototoxicity in three murine strains and effects on NKCC1 of stria vascularis / 中华医学杂志(英文版)

ABSTRACT

<p><b>BACKGROUND</b>After establishing a murine model of aminoglycoside antibiotic (AmAn) induced ototoxicity, the sensitivity of AmAn induced ototoxicity in three murine strains and the effect of kanamycin on the expression of Na-K-2Cl cotransporter-1 (NKCC1) in stria vascularis were investigated.</p><p><b>METHODS</b>C57BL/6J, CBA/CaJ, NKCC1(+/-) mice (24 of each strain) were randomly divided into four experimental groups A kanamycin alone; B kanamycin plus 2, 3-dihydroxybenzoate; C 2, 3-dihydroxybenzoate alone; and D control group. Mice were injected with kanamycin or/and 2, 3-dihydroxybenzoate twice daily for 14 days. Auditory brainstem response (ABR) was measured and morphology of cochlea delineated with succinate dehydrogenase staining. Expression of NKCC1 in stria vascularis was detected immunohistochemically.</p><p><b>RESULTS</b>All three strains in groups A and B developed significant ABR threshold shifts (P < 0.01), which were accompanied by outer hair cell loss. NKCC1 expression in stria vascularis was the weakest in group A (A cf D, P < 0.01) and the strongest in groups C and D (P < 0.05). CBA/CaJ mice had the highest sensitivity to AmAn.</p><p><b>CONCLUSIONS</b>Administration of kanamycin established AmAn induced ototoxicity. Kanamycin inhibited the expression of NKCC1 in stria vascularis. 2, 3-dihydroxybenzoate attenuated AmAn induced ototoxicity-possibly by enhancing the expression of NKCC1. Age related hearing loss did not show additional sensitivity to AmAn induced ototoxicity in murine model.</p>