Avian cochlear hair cell regeneration: stereological analyses of damage and recovery from a single high dose of gentamicin

Janas, Janice D.; Cotanche, Douglas A.; Rubel, Edwin W.

doi:10.1016/0378-5955(95)00190-5

Cited by 66 publications

(65 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The montages are representative of cochleae 30, 42, 48, 72, and 96 h AI. Phalloidin labeling shows that hair cell loss begins in the very basal (proximal) tip of the basilar papilla around 30 h AI, and progress esapically (distally) with time, similar to previous results describing gentamicininduced avian cochlear hair cell damage (Bhave et al, 1995;Janas et al, 1995;Park et al, 1998;Roberson et al, 2000;Mangiardi et al, 2004;Duncan et al, 2006). Caspase-3 activation is first detected between 30 and 42 h AI, corresponding with the time points where hair cell damage and loss are first seen (Fig.…”

Section: Timeline Of Caspase Activation After Gentamicin Treatmentsupporting

confidence: 70%

“…A single systemic injection of a high dose of gentamicin (an aminoglycoside antibiotic) can create a consistent pattern of hair cell death in the avian cochlea, with cell loss beginning in the basal (proximal) end of the basilar papilla and progressing apically (distally) with time (Bhave et al, 1995;Janas et al, 1995;Park et al, 1998;Roberson et al, 2000;Mangiardi et al, 2004;Duncan et al, 2006). Many studies have characterized changes in avian cochlear hair cells following treatment with gentamicin both in vivo and in vitro.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Comparison of activated caspase detection methods in the gentamicin-treated chick cochlea

et al. 2008

Self Cite

View full text Add to dashboard Cite

Aminoglycoside antibiotics induce caspase-dependent apoptotic death in cochlear hair cells. Apoptosis, a regulated form of cell death, can be induced by many stressors, which activate signaling pathways that result in the controlled dismantling of the affected cell. The caspase family of proteases is activated in the apoptotic signaling pathway and is responsible for cellular destruction. The initiator caspase-9 and the effector caspase-3 are both activated in chick cochlear hair cells following aminoglycoside exposure. We have analyzed caspase activation in the avian cochlea during gentamicin-induced hair cell death to compare two different methods of caspase detection: caspase antibodies and CaspaTag kits. Caspase antibodies bind to the cleaved activated form of caspase-9 or caspase-3 in specific locations in fixed tissue. CaspaTag is a fluorescent inhibitor that binds to a reactive cysteine residue on the large subunit of the caspase heterodimer in unfixed tissue.To induce cochlear hair cell loss, 1-2 week-old chickens received a single injection of gentamicin (300 mg/kg). Chicks were sacrificed 24, 30, 42, 48, 72, or 96 h after injection. Cochleae were dissected and labeled for activated caspase-9 or caspase-3 using either caspase-directed antibodies or CaspaTag kits. Ears were co-labeled with either phalloidin or myosin VI to visualize hair cells and to determine the progression of cochlear damage. The timing of caspase activation was similar for both assays; however, caspase-9 and caspase-3 antibodies labeled only those cells currently undergoing apoptotic cell death. Conversely, CaspaTag-labeled all the cells that have undergone apoptotic cell death and ejection from the sensory epithelium, in addition to those that are currently in the cell death process. This makes CaspaTag ideal for showing an overall pattern or level of cell death over a period of time, while caspase antibodies provide a snapshot of cell death at a specific time point.

show abstract

Section: Timeline Of Caspase Activation After Gentamicin Treatmentsupporting

confidence: 70%

Section: Introductionmentioning

confidence: 99%

Comparison of activated caspase detection methods in the gentamicin-treated chick cochlea

et al. 2008

Self Cite

View full text Add to dashboard Cite

show abstract

“…Support cell proliferation occurs between 1 and 7 d after gentamicin injection, with a peak in nucleotide incorporation occurring at 3 d (Bhave et al, 1995). By 5 d after injection, hair cell regeneration is apparent, because small cells with immature stereocilia bundles are detectable by scanning electron microscopy (Bhave et al, 1995;Janas et al, 1995), and these cells label with tritiated thymidine when it is continually provided after damage (Roberson et al, 1996).…”

Section: Histology Of the Normal And Drug-damaged Cochlear Epitheliummentioning

confidence: 99%

“…First, no double-labeled cells are present in the basal, damaged region at 2 hr after thymidine injection, when almost all cells remaining in that region are support cells. Second, the time of appearance of double-labeled cells (at 24 hr after thymidine/BrdU injection or 4 d after gentamicin injection) corresponds to the time when stereocilia bundles of regenerating hair cells first emerge in the damaged region after a single gentamicin injection (Bhave et al, 1995;Janas et al, 1995;W. R. Lippe, personal communication).…”

Section: Mechanisms Of Hair Cell Differentiation During Regeneration mentioning

confidence: 99%

“…The ototoxic drug gentamicin, when delivered as a single intraperitoneal injection at 100 -400 mg/kg, causes a basal-to-apical progression of hair cell loss throughout the basal, high frequency portion of the basilar papilla (Bhave et al, 1995;Janas et al, 1995). Hair cell loss is detectable by 1 d after injection in the basal tip of the basilar papilla, and it spreads to include the basal one third (ϳ 800 M) of the epithelium by 3-5 d after injection (Fig.…”

Section: Histology Of the Normal And Drug-damaged Cochlear Epitheliummentioning

confidence: 99%

See 1 more Smart Citation

Hair Cell Differentiation in Chick Cochlear Epithelium after Aminoglycoside Toxicity:In VivoandIn VitroObservations

Leaño²,

et al. 1996

View full text Add to dashboard Cite

Inner ear epithelia of mature birds regenerate hair cells after ototoxic or acoustic insult. The lack of markers that selectively label cells in regenerating epithelia and of culture systems composed primarily of progenitor cells has hampered the identification of cellular and molecular interactions that regulate hair cell regeneration. In control basilar papillae, we identified two markers that selectively label hair cells (calmodulin and TUJ1 ␤ tubulin antibodies) and one marker unique for support cells (cytokeratin antibodies). Examination of regenerating epithelia demonstrated that calmodulin and ␤ tubulin are also expressed in early differentiating hair cells, and cytokeratins are retained in proliferative support cells. Enzymatic and mechanical methods were used to isolate sensory epithelia from mature chick basilar papillae, and epithelia were cultured in different conditions. In control cultures, hair cells are morphologically stable for up to 6 d, because calmodulin immunoreactivity and phalloidin labeling of filamentous actin are retained. The addition of an ototoxic antibiotic to cultures, however, causes complete hair cell loss by 2 d in vitro and generates cultures composed of calmodulinnegative, cytokeratin-positive support cells. These cells are highly proliferative for the first 2-7 d after plating, but stop dividing by 9 d. Calmodulin-or TUJ1-positive cells reemerge in cultures treated with antibiotic for 5 d and maintained for an additional 5 d without antibiotic. A subset of calmodulinpositive cells was also labeled with BrdU when it was continuously present in cultures, suggesting that some cells generated in culture begin to differentiate into hair cells. Key words: hair cells; regeneration; chick; basilar papilla; cell culture; differentiationHair cells are sensory receptors for hearing, equilibrium, and motion detection. Some animals demonstrate the capacity to generate hair cells throughout their lifetime (Popper and Hoxter, 1984;Corwin, 1985; Jörgenson and Mathiessen, 1989;Roberson et al., 1992) or to initiate hair cell regeneration in the event of their loss (Corwin and Cotanche, 1988;Ryals and Rubel, 1988). The progenitors of hair cells seem to be a subset of support cells that reside adjacent to hair cells in the sensory epithelia (Girod et al., 1989;Balak et al., 1990;Raphael, 1992;Hashino and Salvi, 1993;Weisleder and Rubel, 1993;Stone and Cotanche, 1994;Tsue et al., 1994a;Roberson et al., 1996). Although mature mammals normally do not generate new hair cells, recent in vivo and in vitro studies have documented mitotic activity and immature-looking hair cells in mammalian vestibular epithelia after exposure to ototoxic drugs Warchol et al., 1993;Rubel et al., 1995), suggesting that hair cell regeneration in mammals may be inducible. The development of culture methods for mature cochlear and vestibular end organs has been initiated to identify molecules that regulate cell proliferation and differentiation in avian and mammalian hair cell epithelia. Co-culture experiments suggest that...

show abstract

N-Chlorotaurine, a Novel Endogenous Antimicrobial Agent

Neher

Nagl²,

Schrott‐Fischer³

et al. 2001

Arch Otolaryngol Head Neck Surg

View full text Add to dashboard Cite

Objective: To investigate the tolerability of Nchlorotaurine, a new antimicrobial agent, by application to the middle ear in a mouse model. Methods:Five BALB/c mice were each injected through the tympanic membrane with 5 µL of 0.1%, 1.0%, and 10% N-chlorotaurine and compared with animals in which 0.9% isotonic sodium chloride solution, 0.2% gentamicin sulfate, and 0.25% trimethyltin chloride were instilled. Auditory brainstem responses to clicks were evaluated repeatedly between 4 and 75 days after injection, and histologic investigations of the inner ear were performed subsequently. Three additional groups of mice were injected with isotonic sodium chloride solution, 1.0% Nchlorotaurine, and 0.25% trimethyltin, and brainstem responses to tone bursts of 8, 16, and 32 kHz were tested. In addition, the middle ear was examined histologically.Results: Mice treated with isotonic sodium chloride solution, 0.1% N-chlorotaurine, and 0.2% gentamicin sulfate did not show changes in response threshold. Treatment with 1.0% and 10% N-chlorotaurine caused a reversible increase in auditory brainstem response threshold by 20 dB 4 days after application because of local irritation around the perforation of the tympanic membrane. In contrast, 0.25% trimethyltin showed a permanent elevation of auditory brainstem response threshold of 10 to 15 dB and a scattered loss of outer hair cells predominantly in the apical turn. No alterations of the inner ear were observed in the other treatment groups. The mucous membrane of the middle ear remained unaffected in all test groups. Conclusion:Application of N-chlorotaurine to the middle ear is well tolerated without adverse effects and may be a useful new endogenous antimicrobial agent for local treatment of otologic infections.

show abstract

Avian cochlear hair cell regeneration: stereological analyses of damage and recovery from a single high dose of gentamicin

Cited by 66 publications

References 30 publications

Comparison of activated caspase detection methods in the gentamicin-treated chick cochlea

Comparison of activated caspase detection methods in the gentamicin-treated chick cochlea

Hair Cell Differentiation in Chick Cochlear Epithelium after Aminoglycoside Toxicity:In VivoandIn VitroObservations

N-Chlorotaurine, a Novel Endogenous Antimicrobial Agent

Contact Info

Product

Resources

About