Aging outer hair cells (OHCs) in the Fischer 344 rat cochlea: Function and morphology

The Fischer 344 rat as a model of presbycusis

“…The possible differences between these two substrains in age-related hearing loss may result from the approximately sixty years genetic drift in their breeding. The results of the studies from our laboratory (Popelář et al, 2003Buckiová et al, 2006Buckiová et al, , 2007 were obtained from the F344/DuCrl substrain obtained from Charles River Wiga, Sulzfeld, Germany, whereas those from the laboratory of D. Henderson Hu et al, 2008;Chen et al, 2009) were obtained from the F344/ NHsd substrain obtained from Harlan Laboratories. Most of the data are identical or similar; if there are differences, they will be indicated.…”

“…The deletion of prestin expression results in a loss of OHC electromotility and a loss of DPOAEs (Liberman et al, 2002). Chen et al (2009) proposed a hypothesis that reactive oxygen species, which accumulate during aging in Fischer344 rats, target the prestin protein. This process can lead to the oxidation of amino acid residue side chains, the formation of protein-protein cross-linkage and the oxidation of the protein backbone resulting in protein fragmentation.…”

Too much of a good thing: Long-term treatment with salicylate strengthens outer hair cell function but impairs auditory neural activity

“…Since age-related hearing loss appeared to be related to a reduction of prestin in OHC (Chen et al , 2009), we hypothesized that chronic salicylate treatment would increase prestin expression and enhance DPOAE thereby restoring auditory function in aged Fischer 344/NHsd (F344) rats. Although DPOAE were generally enhanced or remained at the pre-exposure levels after the chronic salicylate treatment; we unexpectedly observed a permanent reduction in CAP amplitude.…”

Age-related decline of the cytochrome c oxidase subunit expression in the auditory cortex of the mimetic aging rat model associated with the common deletion

“…And Fischer 344 rats provide a valuable alternative model for the investigation of presbycusis comparable with the C57BL/6J mice. Fischer 344 rats differ from most other strains of rats by the rapid deterioration of distortion product otoacoustic emissions (DPOAE), with the majority of outer hair cells (OHC) being present and morphologically intact (Chen et al, 2009;Syka, 2010). The physical occurrence of hair cells in the cochlea of F344 rats, even in very old subjects, suggests that the reasons for the disappearance of DPOAE and the increase of auditory brainstem responses (ABR) threshold must be different from those in man, where presbycusis is connected with hair cell loss (Syka, 2010).…”