You are here:
DEVELOPMENT OF AN OBJECTIVE AND QUANTIFIABLE TERATOLOGICAL SCREEN FOR USE IN ZEBRAFISH LARVAE.
Citation:
PADNOS, B. K. DEVELOPMENT OF AN OBJECTIVE AND QUANTIFIABLE TERATOLOGICAL SCREEN FOR USE IN ZEBRAFISH LARVAE. Presented at Society of Toxicology, Seattle, WA, March 16 - 20, 2008.
Impact/Purpose:
To address EPA’s need to prioritize large numbers of chemicals for testing, a rapid, cost-effective in vivo screen for potential developmental toxicity using an alternative vertebrate species (zebrafish;Danio rerio) has been developed.
Description:
To address EPA’s need to prioritize large numbers of chemicals for testing, a rapid, cost-effective in vivo screen for potential developmental toxicity using an alternative vertebrate species (zebrafish;Danio rerio) has been developed. A component of that screen is the observation and characterization of the teratological changes elicited by toxicant exposure. In order to compare these teratological changes across doses and across chemicals, a teratological scoring system (TSS) has been developed that both identifies and quantifies these changes. Zebrafish embryos were individually exposed to toxicants for 5 days in a 96-well microtiter plate, one embryo per well (26°C, 14:10 light:dark cycle, all solutions are renewed daily). On the 6th day post fertilization (1 day after exposure had ceased), the fry were observed under a dissecting microscope. Using the TSS the fry were observed for abnormalities in 4 different body areas (spine, fins, cranial/facial, thorax and abdomen), as well as body position in the water column. A list of possible terata was compiled, each identified by an alphabetic character, and the degree of the abnormality was graded using a score of 0 to 4, with 0 signifying no deviation form normal,1 indicating a slight change, and 4 representing the greatest deviation from normal. Each fry was scored by an observer blinded to the treatment using both the alphabetical and numerical label. The scores were totaled to indicate an overall teratogenic effect of the toxicant, as well as the domain and degree in which majority of the changes occurred. The total scores according to toxicant and concentration was then compared to arrive at a mean teratogenic effect of a toxicant.