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Maria L. Esparza 1, Dr. Louise Abbott 1

Zebrafish as a model organism for neurotoxicity testing of low-dose methylmercury exposure

1 Department of Veterinary Integrative BioSciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, State, USA

Structured Abstract

Objective – To examine the individual effects of low dose methylmercury exposure on developing zebrafish nervous system by accessing cell proliferation and death. 

Animals or Sample Population 32 hour-post fertilization wild type zebrafish embryos

Procedure - Immunohistochemistry and histochemistry staining completed on paraformaldehyde fixed and sectioned zebrafish embryos.

Results – While no results were statistically significant there were several trends noted.  At a dose of 10 parts per billion (PPB), exposed zebrafish embryos tended to show reduced proliferation and increased neuronal cell death in the developing CNS compared to age-matched control embryos.  Doses of 50 ppb abd 100 ppb resulted in increased embryonic lethality compared to 10 ppb and 0 ppb exposures.

Conclusions and Clinical Relevance – 24 hour exposure to low doses of methylmercury may adversely impact CNS development.

Impact for Human Medicine – Low-dose methylmercury exposure to the developing human CNS continues to be of concern and such exposures may have serious detrimental impact on cognitive and motor functions of exposed individuals.