|
(T/EH062) Histological determinants in the evaluation of endocrine disruption on reproductive fitness in fish. van der Ven, Leo1, Wester, Piet1, van den Brandhof, Evert-Jan2, Folkerst, Ariejan2, Bulder, Astrid2, Drüke, Jeanette2, Beekhof, Piet2, 1 2 ABSTRACT- There is a clear need for effective screening tools for the evaluation of endocrine disruptive effects on reproductive fitness in aquatic organisms. Histological analysis is a method which can detect causative relations of stressor and effects on one hand, and which may disclose the impact of (endocrine disrupting) pollutants on the level of individual or group fitness on the other hand. Indications of causative relations can be deduced from the experimental setting, where exposures to endocrine disrupting compounds can be linked to histological changes in target tissues. Simultaneously, the induced histological changes may be interpreted as functional disturbances, and thus indicate effects on reproductive fitness of the exposed individuals or groups. Moreover, specific histological findings in field specimen can be linked with experimental findings. Optimal employment of histology as a screening tool can be achieved by further standardisation of this method. We are designing a standard system by which histological changes in particularly the reproductive system of fish can be documented routinely. For this purpose we use zebrafish as a model, and the studied determinants are 1) in the adults: gonad size, relative presence of various stages of oocyte/sperm maturation, oviduct content, vitellogenin expression, intersex; and 2) in juveniles: sex ratio, developmental stage of the gonads. Qualitative and (semi-)quantitative examples of this routine system are presented to illustrate the discriminative potential with respect to various exposure regimes and experimental conditions, and to demonstrate the power of histology as a routine screening tool. Key words: histological pathology in fish, endocrine disruption, screening methods, reproductive system |
