Fish toxicologic pathology: the growing credibility gap and how to bridge it

Histopathology is a mainstay of laboratory and environmental fish toxicology studies. This versatile endpoint can be used to screen for effects of chemical exposures, determine no effect concentrations, provide clues to modes/mechanisms of action, evaluate the effectiveness of pharmacologic therapies and environmental remediation efforts, and assess the background health of test subjects. Unfortunately, recent reviews of the literature suggest that the credibility of histopathology findings in peer-reviewed journal articles is often less than desirable, and there is evidence that this situation may be worsening. Key weaknesses include inadequate experimental design, inferior histologic preparation, inaccurate diagnostic interpretation, inexpert manuscript creation, and ineffectual manuscript review. On the brighter side, it is evident that there are multiple stages in the research and reporting process where innovations may be instituted to improve the quality of published histopathology results. This paper will briefly explore the causes of poor data quality in fish toxicology studies, and provide suggestions for bridging the widening credibility gap.