Figure 1

NAC attenuates cochlear degeneration in S1pr2^−/− mice. (A) S1pr2^−/− mice were treated with vehicle or NAC (1 g/kg/day, p.o.) between 1 and 5 weeks of age, then evaluated by ASR. A small cohort of S1pr^+/− littermates were similarly evaluated at 5 weeks as a reference for normal ASR response. (B) Representative appearance of the organs of Corti in the basal turn of the cochlea at 6 weeks of age. S1pr2^+/− mice uniformly present with intact organs of Corti containing the normal complement of three outer hair cells (arrow). S1pr2^−/− mice were characterized by near-complete degeneration (asterisks). S1pr2^−/− mice treated with NAC demonstrated decreased degeneration, although many organs of Corti were characterized by structural abnormalities (arrowhead). (C) Quantitation of the organ of Corti degeneration at 6 weeks of age. Degeneration indicates complete loss of the organ of Corti. (n = 12, * p < 0.05, ** p < 0.01, *** p < 0.001.).