Investigating Environmental Factors Associated with Autism Spectrum Disorder: Effects of Methylene Chloride on Neurodevelopment in Zebrafish

Science Center, Bent Corridor

Recent epidemiological research reports that increased exposure of pregnant mothers to methylene chloride correlates with increased prevalence of Autism Spectrum Disorder (ASD) in their children. Methylene chloride is a volatile organic compound commonly used as a solvent in paints, in the production of pharmaceuticals, and as a propellant for insecticides. However, it is unknown how this chemical impacts brain development or if it regulates known ASD physiology. The purpose of this research is to determine how methylene chloride affects neural development in zebrafish. Embryos were exposed on the day of fertilization to various concentrations of methylene chloride; body and brain morphology was observed via brightfield microscopy, and mRNA expression of genes associated with different cell types were measured using quantitative PCR. Transgenic reporter zebrafish lines were then used to further characterize neuron changes in terms of temporal and anatomical specificity via fluorescence microscopy. Initial results indicate methylene chloride exposure can (1) induce dose-dependent changes in overall development of zebrafish embryos, (2) downregulate gene expression of neuron cell markers, and (3) result in abnormal GABA neuron anatomy. Long-term, characterizing the molecular impact of methylene chloride on brain development may contribute to the improvement of ASD therapeutic treatments and inform data-driven environmental regulations.