Science Inventory

Dechorionation of Zebrafish Embryos on Day 1 Post Fertilization Alters Response to an Acute Chemical Challenge at 6 Days Post Fertilization

Citation:

Wesstrom, S., D. Korest, D. Hunter, AND S. Padilla. Dechorionation of Zebrafish Embryos on Day 1 Post Fertilization Alters Response to an Acute Chemical Challenge at 6 Days Post Fertilization. Carolinas SETAC, Durham, North Carolina, April 25 - 27, 2018.

Impact/Purpose:

Dechorionation is a method used to enable image acquisition in embryonic and larval zebrafish studies. As it is assumed that dechorionation has no long-term effects on fish embryo development, it is important to determine if that assumption is correct. The present study showed that dechorionation may not be a benign procedure, and raise the possibility that dechorionation may disrupt the development of larval zebrafish.

Description:

Dechorionation is a method used to enable image acquisition in embryonic and larval zebrafish studies. As it is assumed that dechorionation has no long-term effects on fish embryo development, it is important to determine if that assumption is correct. The present study explored the behavioral consequences of a commonly-used protease-based enzymatic dechorionation method. Embryos were dechorionated at 28 hours post fertilization by immersion in pronase (20 units/ml of 10% Hanks’ balanced salt solution) with agitation at 26°C for 3 minutes. Control embryos were subjected to the same protocol without pronase. To determine whether dechorionation affected the response to an acute chemical challenge, larvae were neurochemically challenged by immersion in 1 µM of the cholinesterase inhibitor chlorpyrifos at 6 days post fertilization (5 days after the dechorionation). Locomotor behavior was assessed in 4 x 16 min alternating light/dark periods for 64 minutes. There was no difference in the overall activity of the dechorionated animals compared to those with their chorions left intact. In contrast, the change in locomotor activity induced by chlorpyrifos differed based on whether or not the larva was dechorionated on day 1 (p= .037). Exposure to chlorpyrifos increased activity in larvae that had had intact chorions during development, but chlorpyrifos-induced hyperactivity was not observed in the previously dechorionated larvae. These data show that dechorionation may not be a benign procedure, and raise the possibility that dechorionation may disrupt the development of larval zebrafish. This abstract may not necessarily reflect official Agency Policy.

Record Details:

Record Type: DOCUMENT (PRESENTATION/POSTER)
Product Published Date: 04/27/2018
Record Last Revised: 06/14/2018
OMB Category: Other
Record ID: 341116

Organization:

U.S. ENVIRONMENTAL PROTECTION AGENCY

OFFICE OF RESEARCH AND DEVELOPMENT

NATIONAL HEALTH AND ENVIRONMENTAL EFFECTS RESEARCH LABORATORY

INTEGRATED SYSTEMS TOXICOLOGY DIVISION

GENETIC AND CELLULAR TOXICOLOGY BRANCH