Presentation Title

A Reference Atlas of Thyroid Histology of Pseudacris regilla: An Adaptation of the OECD Amphibian Metamorphosis Assay to Accommodate a Species Native to North America

Format of Presentation

Poster to be presented Friday March 31, 2017

Abstract

Several frog, and other amphibian, populations have been dramatically declining in recent years, and many species are on the brink of extinction. There is mounting evidence that anthropogenically derived environmental pollutants are contributing to amphibian population declines. Amphibians have long been used to study the effects of pollutants, and have unique attributes, such as increased skin permeability and thyroid hormone dependent metamorphic development, that warrant careful consideration during toxicity testing. The Organization for Economic Co-operation and Development (OECD) published a guideline in 2009 for a laboratory-based in vivo assay, the Amphibian Metamorphosis Assay. This assay is mainly used to screen for chemicals that disrupt the hypothalamic endocrine axis using methods specific to Xenopus laevis, a solely aquatic species found in Sub-Saharan Africa. Previous studies in our lab have examined the molecular and morphometric adverse endpoints in the AMA using a semi-aquatic amphibian species native to North America (Pseudacris regilla), but to date no histopathology has been reported in this species. Therefore, the objective of this study was to develop an atlas of thyroid development for Gosner stages 25 to 43 Pseudacris regilla. This atlas will serve as a reference for the normal histology of thyroid development throughout key periods during metamorphosis in this species, and further facilitate the use of this native North American amphibian in environmental toxicity testing regimes.

Department

Biological Sciences

Faculty Advisor

Allan Arndt and Vicki Marlatt

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A Reference Atlas of Thyroid Histology of Pseudacris regilla: An Adaptation of the OECD Amphibian Metamorphosis Assay to Accommodate a Species Native to North America

Several frog, and other amphibian, populations have been dramatically declining in recent years, and many species are on the brink of extinction. There is mounting evidence that anthropogenically derived environmental pollutants are contributing to amphibian population declines. Amphibians have long been used to study the effects of pollutants, and have unique attributes, such as increased skin permeability and thyroid hormone dependent metamorphic development, that warrant careful consideration during toxicity testing. The Organization for Economic Co-operation and Development (OECD) published a guideline in 2009 for a laboratory-based in vivo assay, the Amphibian Metamorphosis Assay. This assay is mainly used to screen for chemicals that disrupt the hypothalamic endocrine axis using methods specific to Xenopus laevis, a solely aquatic species found in Sub-Saharan Africa. Previous studies in our lab have examined the molecular and morphometric adverse endpoints in the AMA using a semi-aquatic amphibian species native to North America (Pseudacris regilla), but to date no histopathology has been reported in this species. Therefore, the objective of this study was to develop an atlas of thyroid development for Gosner stages 25 to 43 Pseudacris regilla. This atlas will serve as a reference for the normal histology of thyroid development throughout key periods during metamorphosis in this species, and further facilitate the use of this native North American amphibian in environmental toxicity testing regimes.