Study of species Lithobates catesbeianus as alternative organism for teratogenic tests

• Grant number: 14/07293-6
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: October 01, 2014
• End date: September 30, 2016
• Field of knowledge: Agronomical Sciences - Fishery Resources and Fishery Engineering - Aquaculture
• Agreement: Coordination of Improvement of Higher Education Personnel (CAPES)
• Principal Investigator: Cláudia Maris Ferreira Mostério
• Grantee: Fernanda Menezes França
• Host Institution: APTA Regional. Agência Paulista de Tecnologia dos Agronegócios (APTA). Secretaria de Agricultura e Abastecimento (São Paulo - Estado). Campinas , SP, Brazil

Abstract

The FETAX (Frog Embryo Teratogenesis Assay - Xenopus) regulated by ASTM E 1439-98 (2012) is a bioassay used to determine the teratogenic potenctial of chemicals in Xenopus laevis embryos. Although it was designed for this kind of species, the standard allows the use of alternative species. The aim of this study is to adapt the protocol FETAX to Lithobates catesbeianus. For that, after we establish the best method for obtaining hormonal induction of spawning, we intend to: determine the duration of the test FETAX for this species; establish the sensitivity ranges of the embryos to 6-aminonicotinamide, cyclophosphamide and sodium chloride (LC50 and EC50, teratogen index) and thus define the most suitable reference substance for the species; and establish and validate the repeatability of the test. With the standardization of specific protocol to the species the test can be used in other laboratories and researchers institutes. This assay can be an excellent tool to evaluate products for regulatory purpose and for monitoring impacted environments. The first stage aims to improve the method of inducing ovulation. Four groups totalizing 32 females will be separated in following treatments: only LHRHa, pimozide, risperidone and metoclopramide associated with LHRHa. After that the development of the eggs will be assessed by determining the time of exposure and sensitivity ranges for the reference toxicant tested, following the recommendations of the standard conform the species. This study intends to contribute to the advancement of ecotoxicology and for the frogculture in Brazil, developing and implementing new methodologies from existing international protocols, establishing bases to the use of L. catesbeianus in teratogenic testing and besides improving the technique of reproduction by induction for the species. (AU)