Acoustic injury in mice: 129/SvEv is exceptionally resistant to noise-induced hearing loss

129/SvEv is an inbred mouse strain popular for use in genetic knockout stud ies. Here, we compare normal auditory function and vulnerability to acousti c injury in wild-type mice of the 129/SvEv vs. CBA/CaJ strains. Compound ac tion potentials (CAPs) and distortion product otoacoustic emissions (DPOAEs ) showed slightly higher thresholds for 129/SvEv re CBA/CaJ, especially at frequencies > 20 kHz. Middle-ear motion (i.e. umbo velocity) was similar in the two strains; although frequencies > 20 kHz could not be evaluated. Per manent threshold shift (PTS) and hair cell losses, measured 1 week after hi gh-intensity exposure to an 8-16 kHz noise band, were smaller in 129/SvEv a t all exposure levels and durations from 97 dB SPL x 2 h to 106 dB SPL x 8 h. Furthermore, PTS growth with increasing exposure energy was slower in 12 9/SvEv(< 2 dB/dB) than CBA/CaJ (9 dB/dB). These data suggest that the vulne rability differences lie in the inner ear, not the middle ear. Several 129/ Sv substrains show age-related hearing loss (AHL): 129/SvEv has not yet bee n evaluated (Zheng, Q.Y., Johnson, K.R., Erway, L.C., 1999. Assessment of h earing in 80 inbred strains of mice by ABR threshold analyses. Hear. Res. 1 30, 94-107). Thus, although other strains with AHL, e.g. C57Bl/6J, show inc reased vulnerability to noise-induced hearing loss (NIHL), pairing of AHL a nd NIHL vulnerabilities may not be obligatory. (C) 2000 Elsevier Science B. V. All rights reserved.