Organophosphate Pesticide Effects on Neuronal Cytoarchitecture and Morphological Abnormalities in 72 hour Zebrafish Embryos

Abstract

Organophosphate pesticides (OP) are a class of acetylcholinesterase (AChE) inhibitors, which have effects on the central and peripheral nervous systems. OP's inhibit AChE through phosphorylation of the active site serine, which leads to a toxic and potentially lethal buildup of the neurotransmitter acetylcholine (ACh) causing excess stimulation of cholinergic neurons. OP's are widely used to suppress the activity and growth of insect pest populations in both agriculture and household settings. The objective of this study was to examine both organismal and cellular morphological changes caused by OP exposure. Specifically, zebrafish (Danio Rerio) embryos were exposed to sub‐lethal concentrations of Chlorpyrifos (CPF) and its bioactive form Chlorpyrifos‐oxon (CPO), and compared to vehicle controls (MeOH). Gross morphological changes were observed at 72 hours via light microscopy and morphological changes to cholinergic neurons were observed via confocal microscopy of wholemount immuno‐labeled embryos using anti‐ChAT. Light microscopy observations of the embryos showed varying degrees of cardiac edema in both CPF and CPO exposed embryos. Additionally, mild kyphosis was observed in CPF and strong kyphosis in CPO exposed embryos. Confocal observations of the trunk spinal region showed embryos exposed to CPF lost dorsal neural tube cell staining and dark pockets, possibly indicating cell death, were observed along the ventral neural tube. For CPO exposed embryos, cells bodies in the neural tube were disorganized. Additionally, axon projections across the neural tube showed differences in branching and spacing in both CPF and CPO exposed embryos. Together our results showed that OP exposure causes changes in neuronal cytoarchitecture and embryo morphology. Understanding the developmental effects of these pesticides is particularly important since developmental changes have significant effects on adult systems and children represent a vulnerable population.Support or Funding InformationDepartment of Defense, ARO 66377‐RT‐REP; Keck Foundation Undergraduate Fellowship to T.H.W.; James Irvine Foundation Chair in Biological Sciences to E.A.F.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.