Author(s)
Michelle K. Hong, BS
Kristen A. Echanique, MDLarry F. Hoffman, PhD
Ashley E. Kita, MD
Affiliation(s)
Abstract:
<br/><b>Background:</b> Recent evidence indicates that compromise to Schwann cells ensheathing inner ear afferent neurons results
in inner ear dysfunction mimicking drug-induced ototoxicity. Cisplatin and aminoglycosides are widely prescribed but
known to cause ototoxicity. While both drugs have been shown to induce peripheral nerve demyelination, demyelination of
spiral or Scarpa’s ganglion neurons has not been extensively studied. There is a need for a model for ototoxic demyelination
to screen medications for injurious or protective potential in Schwann cells.
Hypothesis: An in vitro model of Schwann cells can be used to evaluate the potential of cisplatin and gentamicin to
compromise their viability, thereby identifying risk factors for demyelination.
<br/><b>Methods:</b> Rat Schwann RT4-D6P2T cells were seeded on 96-well plates 18-24 hours prior to treatment with cisplatin or
gentamicin. Cell viability was evaluated 24 hours after treatment with the MTT cell proliferation assay.
<br/><b>Results:</b> Dose-response curves were created using 4-parameter log logistic regression models. LC50 doses for cisplatin and
gentamicin were 29.6µM (p=1.606E-11) and 2.0mM (p=1.035E-10) respectively, reflecting an approximate 64 fold
difference.
<br/><b>Conclusions:</b> Our RT4-D6P2T toxicity assay provides a high-throughput in vitro model for exploring Schwann cell
sensitivity to ototoxins suggestive of demyelinating pathology. We demonstrated dose-dependent reductions in cell viability
from cisplatin and gentamicin with significantly greater sensitivity to cisplatin. This suggests that cisplatin exhibits a greater
potential than gentamicin for compromising Schwann cells and that cisplatin may cause demyelination-induced afferent
neuron hypofunction in the inner ear. This assay is also well-positioned to screen for protective agents to preserve afferent
neuron function during chemotherapy.
*Professional Practice Gap & Educational Need: There is a need for a high-throughput method of testing pharmacologic
agents to rehabilitate or prevent ototoxic injury from widely prescribed drugs such as gentamicin and cisplatin.
*Learning <br/><b>Objective:</b> To highlight demyelination as a potential mechanism for cisplatin ototoxicity and an important
pathway to consider for rehabilitation. To develop a high-throughput method of screening multiple pharmacologic agents
for rehabilitation benefit.
*Desired <br/><b>Result:</b> To identify a rehabilitation agent for ototoxic demyelination in vitro and further study this agent as a drug
of choice for mitigating ototoxicity in a clinical setting
*Level of Evidence – N/A
*Indicate IRB or IACUC : Exempt