Hepatotoxicity Testing in Larval Zebrafish - Zebrafish: Methods for Assessing Drug Safety and Toxicity - page 91

effects directly to the liver, and some nontoxic controls. When assessed using the
described methods, a distinct change in hepatic morphology was reported for certain
compounds. In affected larvae, the organ appeared darker than controls with a brown
and gray coloration, the texture of the tissue had become amorphous, and the outer
edge of the organ was more diffuse, making it more difficult to distinguish liver from
the surrounding tissues, especially in cases where secondary or gross toxicity was also
induced (Fig. 8.2). Similar phenotypes have also been reported in other studies such as
for brefeldin A (Zhang et al., 2003). Although these characteristics are typical for
necrotic tissue when viewed at this magnification, histology would need to be
Figure 8.2 Phenotypic identification of hepatotoxicity at 120hpf. (a) Control larvae exhibiting a clear,
healthy liver at 120hpf. (b) Larva treated with a hepatotoxin for 48 h exhibiting tissue degradation,
hepatomegaly, and yolk retention. L, Liver; Y, yolk retention. (See the color version of this figure in Color
Plates section.)