Article

Using the Zebrafish Lateral Line to Screen for Ototoxicity

Department of Otolaryngology-Head and Neck Surgery, University of Washington, Box 356515, Seattle, WA 98195, USA.
Journal of the Association for Research in Otolaryngology (Impact Factor: 2.6). 07/2008; 9(2):178-90. DOI: 10.1007/s10162-008-0118-y
Source: PubMed

ABSTRACT

The zebrafish is a valuable model for studying hair cell development, structure, genetics, and behavior. Zebrafish and other aquatic vertebrates have hair cells on their body surface organized into a sensory system called the lateral line. These hair cells are highly accessible and easily visualized using fluorescent dyes. Morphological and functional similarities to mammalian hair cells of the inner ear make the zebrafish a powerful preparation for studying hair cell toxicity. The ototoxic potential of drugs has historically been uncovered by anecdotal reports that have led to more formal investigation. Currently, no standard screen for ototoxicity exists in drug development. Thus, for the vast majority of Food and Drug Association (FDA)-approved drugs, the ototoxic potential remains unknown. In this study, we used 5-day-old zebrafish larvae to screen a library of 1,040 FDA-approved drugs and bioactives (NINDS Custom Collection II) for ototoxic effects in hair cells of the lateral line. Hair cell nuclei were selectively labeled using a fluorescent vital dye. For the initial screen, fish were exposed to drugs from the library at a 100-muM concentration for 1 h in 96-well tissue culture plates. Hair cell viability was assessed in vivo using fluorescence microscopy. One thousand forty drugs were rapidly screened for ototoxic effects. Seven known ototoxic drugs included in the library, including neomycin and cisplatin, were positively identified using these methods, as proof of concept. Fourteen compounds without previously known ototoxicity were discovered to be selectively toxic to hair cells. Dose-response curves for all 21 ototoxic compounds were determined by quantifying hair cell survival as a function of drug concentration. Dose-response relationships in the mammalian inner ear for two of the compounds without known ototoxicity, pentamidine isethionate and propantheline bromide, were then examined using in vitro preparations of the adult mouse utricle. Significant dose-dependent hair cell loss in the mouse utricle was demonstrated for both compounds. This study represents an important step in validating the use of the zebrafish lateral line as a screening tool for the identification of potentially ototoxic drugs.

Download full-text

Full-text

Available from: David W Raible, Jan 20, 2014
    • "Since genetic manipulation may be performed in zebrafish, the biological targets and modes of action of various compounds might be determined. Further, zebrafish have already been used as an established model organism in numerous studies that assess toxicity endpoints of compounds or their mechanisms of action (Berghmans et al. 2007; Tran et al. 2007; Chiu et al. 2008; Richards et al. 2008; Winter et al. 2008; Weber et al. 2015). Thus, the present study aimed to investigate the developmental toxicity, apoptotic induction, and mechanism of toxicity of the aqueous extract of M. pachycarpa (AEMP) using zebrafish as model organism. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Extensive and indiscriminate use of synthetic compounds and natural compounds obtained from plant sources have resulted in serious threats to the aquatic ecosystem and human health. Aqueous extract of the root of the plant, Milletia pachycarpa Benth, is currently used for killing fish in the state of Manipur, India. Moreover, this plant is also used as traditional medicine in this region. Although it is widely used in traditional medicine, there is limited information available regarding the adverse effects and mechanism underlying its toxicity. This study examined the effects of exposure to aqueous extract of M. pachycarpa (AEMP) on early embryonic development of zebrafish embryos and mechanisms underlying toxicity. Zebrafish embryos treated with different concentrations of the AEMP produced embryonic lethality and developmental defects. The 96-hr-LC50 of AEMP was found to be 4.276 µg/mL. Further, multiple developmental abnormalities such as pericardial edema, yolk sac edema, spinal curvature, swim bladder deflation, decreased heart rate, and delayed hatching were also observed in a dose-dependent manner. Zebrafish embryo showing moderate-to-severe developmental defects following AEMP exposure cannot swim properly. Further, this study examined oxidative stress and apoptosis in embryos exposed to AEMP. Enhanced production of ROS and apoptosis was found in brain, trunk, and tail of zebrafish embryos treated with AEMP. Data suggest that oxidative stress and apoptosis are associated with AEMP-induced embryonic lethality and developmental toxicity in zebrafish embryos.
    No preview · Article · Sep 2015 · Toxicological and Environmental Chemistry
  • Source
    • "Taking advantage of the zebrafish's external and transparent development, the zebrafish embryo model has been exploited in a wide array of developmental toxicology studies, including skeletal development [46, 47], immune development [48], neurodevelopment [49, 50], cardiovascular development515253, and regeneration54555657. A recent spate of screens have used the zebrafish embryo model to analyze potential developmental toxicity of small molecule libraries previously uncharacterized in in vivo models [44] : unknown contaminants in landfill soil [58]; nanomaterials (reviewed by Fako and Ferguson [59]); and ototoxic drugs [60]. Recent studies illustrate that the zebrafish embryo model can be used to screen and prioritize compounds suspected as human developmental toxicants [61]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The evolutionary conservation of genomic, biochemical, and developmental features between zebrafish and humans is gradually coming into focus, with the end result that the zebrafish embryo model has emerged as a powerful tool for uncovering the effects of environmental exposures on a multitude of biological processes with direct relevance to human health. In this review, we highlight advances in automation, high-throughput screening, and analysis that leverage the power of the zebrafish embryo model for unparalleled advances in our understanding of how chemicals in our environment affect our health and wellbeing.
    Full-text · Article · Dec 2014
  • Source
    • "As far as we know, these results are reported for the first time in zebrafish. Significant dose-dependent hair cell loss in the mouse utricle was demonstrated for both neomycin and gentamicin and this represents an important step in validating the use of the zebrafish lateral line as a screening tool for the identification of potentially ototoxic drugs (Chiu et al., 2008), and supports the use of the zebrafish as a pre-clinical indicator of drug-induced histological and functional ototoxicity (Buck et al., 2012). This study was aimed at providing an experimental model of ototoxicity using the hair cells of the lateral line system as a model, "
    [Show abstract] [Hide abstract]
    ABSTRACT: The hair cells of the lateral line system of fishes are morphologically and physiologically similar to the hair cells of the mammalian inner ear, also sharing its molecular characteristics. For this reason, it has been used as a powerful animal model to analyze in vivo ototoxicity. In this work, we examined the dose-dependent effects of two potent ototoxic aminoglycosides, neomycin and gentamicin, on the hair cells of two selected neuromasts (L1 and T1, the first of the trunk and the terminal located in the fin, respectively) of the lateral line in the ET4 transgenic zebrafish line. The hair cells of this strain selectively and constitutively display fluorescence. The fish were treated for 24 h at different doses (1, 2.5, 5, 10 and 100 μM levels) of both aminoglycosides. Immediately after treatment the morphology and the number of cells in L1 and T were analyzed under a fluorescence microscope. The results show that neomycin and gentamicin have different effects on the hair cell death at the same concentration, showing also different toxicity in L1 and T1 neuromasts. The toxicity observed in the hair cells of T1 neuromast was less than in L1 especially for the gentamicin treatment. These results demonstrate different sensitivity of hair cells of the lateral line to ototoxic drugs according to topographical localization and suggest the in vivo assay of the L1 neuromast of zebrafish larva and low doses of neomycin as an ideal model to study ototoxicity induced by aminoglycosides.
    Full-text · Article · Jul 2014 · Annals of anatomy = Anatomischer Anzeiger: official organ of the Anatomische Gesellschaft
Show more