403
currently only available for a few species of fi shes. As fi sh species differ considerably in the structure and functionality of their inner ear and lateral line, one cannot
readily extrapolate the results from one species to another.
4.3 Ototoxic Drug-Induced Hair Cell Loss
In addition to noise, various ototoxic chemicals can damage lateral line and inner
ear fi sh hair cells causing reduced auditory and vestibular sensory response.
Ototoxin damage to fi sh hair cells has been demonstrated in Atlantic cod ( Gadus
morhua ) (Faucher et al. 2009 ), goldfi sh ( Carassius auratus ) (Ramcharitar and
Brack 2010 ; Ramcharitar and Selckmann 2010 ), Mexican blind cavefi sh ( Astyanax
mexicanus ) (Van Trump et al. 2010 ), the oscar ( Astronotus ocellatus ) (Lombarte
et al. 1993 ; Song et al. 1995 ), and the zebrafi sh ( Danio rerio ) (Hernández et al.
2006 , 2007 ; Santos et al. 2006 ; Olivari et al. 2008 ; Uribe et al. 2013a , b ). These
chemicals include alkaloids (e.g., vinblastine and quinine), aminoglycosides (e.g.,
gentamicin, neomycin, and streptomycin), heavy metals and platinum based chemotherapy drugs (Yan et al. 1991 ; Lombarte et al. 1993 ; Song et al. 1995 ; Harris
et al. 2003 ; Hernández et al. 2006 , 2007 ; Ton and Parng 2005 ; Santos et al. 2006 ;
Chiu et al. 2008 ; Ma et al. 2008 ; Olivari et al. 2008 ; Van Trump et al. 2010 ; Buck
et al. 2012 ; Higgs and Radford 2013 ). Hair cell loss induced by ototoxins can cause
hearing defi cits. For example, zebrafi sh given an injection of gentamicin exhibited
both hair cell loss and auditory threshold shifts (Fig. 6 ; Uribe et al. 2013b ).
Fig. 6 ( a ) Mean (±SE) number of saccular hair cell bundles per 900 μm
2 of epithelia. Signifi cantly
fewer phalloidin-labeled hair bundles were counted at each area along the length of the saccule in
gentamicin-treated animals compared to controls. * p < 0.05, ** p < 0.01, ***p<0.001; n = 6–13 saccules per area per condition. ( b ) Auditory thresholds measured via electrophysiological recordings
of auditory evoked potentials were used to construct audiograms to compare auditory function in
treated and control fi sh. There was a signifi cant auditory threshold shift (* p < 0.05) at almost every
frequency tested in gentamicin-treated fi sh when compared to untreated controls. n = 6 animals per
treatment (modifi ed from Uribe et al. 2013b )
Causes and Consequences of Sensory Hair Cell Damage and Recovery in Fishes
currently only available for a few species of fi shes. As fi sh species differ considerably in the structure and functionality of their inner ear and lateral line, one cannot
readily extrapolate the results from one species to another.
4.3 Ototoxic Drug-Induced Hair Cell Loss
In addition to noise, various ototoxic chemicals can damage lateral line and inner
ear fi sh hair cells causing reduced auditory and vestibular sensory response.
Ototoxin damage to fi sh hair cells has been demonstrated in Atlantic cod ( Gadus
morhua ) (Faucher et al. 2009 ), goldfi sh ( Carassius auratus ) (Ramcharitar and
Brack 2010 ; Ramcharitar and Selckmann 2010 ), Mexican blind cavefi sh ( Astyanax
mexicanus ) (Van Trump et al. 2010 ), the oscar ( Astronotus ocellatus ) (Lombarte
et al. 1993 ; Song et al. 1995 ), and the zebrafi sh ( Danio rerio ) (Hernández et al.
2006 , 2007 ; Santos et al. 2006 ; Olivari et al. 2008 ; Uribe et al. 2013a , b ). These
chemicals include alkaloids (e.g., vinblastine and quinine), aminoglycosides (e.g.,
gentamicin, neomycin, and streptomycin), heavy metals and platinum based chemotherapy drugs (Yan et al. 1991 ; Lombarte et al. 1993 ; Song et al. 1995 ; Harris
et al. 2003 ; Hernández et al. 2006 , 2007 ; Ton and Parng 2005 ; Santos et al. 2006 ;
Chiu et al. 2008 ; Ma et al. 2008 ; Olivari et al. 2008 ; Van Trump et al. 2010 ; Buck
et al. 2012 ; Higgs and Radford 2013 ). Hair cell loss induced by ototoxins can cause
hearing defi cits. For example, zebrafi sh given an injection of gentamicin exhibited
both hair cell loss and auditory threshold shifts (Fig. 6 ; Uribe et al. 2013b ).
Fig. 6 ( a ) Mean (±SE) number of saccular hair cell bundles per 900 μm
2 of epithelia. Signifi cantly
fewer phalloidin-labeled hair bundles were counted at each area along the length of the saccule in
gentamicin-treated animals compared to controls. * p < 0.05, ** p < 0.01, ***p<0.001; n = 6–13 saccules per area per condition. ( b ) Auditory thresholds measured via electrophysiological recordings
of auditory evoked potentials were used to construct audiograms to compare auditory function in
treated and control fi sh. There was a signifi cant auditory threshold shift (* p < 0.05) at almost every
frequency tested in gentamicin-treated fi sh when compared to untreated controls. n = 6 animals per
treatment (modifi ed from Uribe et al. 2013b )
Causes and Consequences of Sensory Hair Cell Damage and Recovery in Fishes