Abstract
Objective: Pharmacologic ototoxicity is well described in the medical literature, yet efficient models are lacking. Aurelia aurita aphyrae, transparent jellyfish with identifiable, easily stained hair cells, are effective models because hair cell changes are readily observed and ototoxicity is manifested behaviorally. We treated ephyrae with various gentamycin dilutions, evaluated motility, and quantified structural changes.
Method: Cultured Aurelia aurita polyps underwent strobilation, yielding ephyrae. Baseline pulsing (P), swimming (S), and orientation (O) values were recorded. Ephyrae were transferred to test tubes containing artificial sea water (ASW) or gentamycin (GM). P, S, and O were scored at 30 minutes, 1 hour, 12 hours, and 24 hours. Ephyrae were fixed in formalin, and hair cells were stained and imaged with confocal microscopy, then analyzed with Metamorph image processing program.
Results: P was impaired in a dose dependent fashion, with controls maintaining baseline P, S, and O values through 48 hours. Impairment of S and O occurred with 3.5 mM GM at 12 and 24 hours. Changes occurred rapidly (within 30 minutes) and were stable at 24 hours. For 6 experiments using 10 ephyrae (n = 60), at 24 hours P was reduced on average from 75 in ASW to 29, 12, and 2 for GM concentrations of 1, 2, and 3.5 mM, respectively (P < .001 in all cases compared with control). Hair cell loss per rhopalia at 48 hours (3.5 mM GM) compared with control was significant (36 vs 43, P < .002), correlating with motility.
Conclusion: The ephyrae model readily demonstrates functional and histological impairments when treated with GM, showing promise as a tool for ototoxicity screening and identification of chemoprotective agents.
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