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Updated: Aug 12, 2026
Whole Retinal Explants from Chicken Embryos for Electroporation and Chemical Reagent Treatments
Published on: September 30, 2015
Exposure to diazinon alters in vitro retinogenesis: retinospheroid morphology, development of chicken retinal cell
L E Paraoanu1, J B Mocko, M Becker-Roeck
1Department of Developmental Biology and Neurogenetics, University of Technology Darmstadt, Institute of Zoology, Schnittspahnstrasse 3, D-64287, Darmstadt, Germany. paraoanu@bio-tu-darmstadt.de
Abstract:
Developing embryos are more vulnerable than adults to acute cholinergic intoxication by anticholinesterases, including organophosphorus pesticides. These agents affect the process of neural development itself, leading to permanent deficits in the architecture of the nervous system. Recent evidence on direct roles of acetylcholinesterase (AChE) on neuronal differentiation provides additional grounds for investigating the developmental toxicity of anticholinesterases. Therefore, the effect of the organophosphate diazinon on the development of chick retinal differentiation was studied by an in vitro reaggregate approach. Reaggregated spheres from dissociated retinal cells of the E6 chick embryo were produced in rotation culture. During the whole culture period of 10 days, experimental cultures were supplemented with different concentrations of the pesticide, from 20 to 120 microM diazinon. The pesticide-treated spheres were reduced in size, and their outer surface was irregular. More importantly, inner structural distortions could be easily traced because the structure of control spheroids can be well characterized by a histotypical arrangement of laminar parts homologous to the normal retina. Acetylcholinesterase activity in diazinon-treated spheres was reduced when compared with controls. As a dramatic effect of exposure to the pesticide, inner plexiform layer (IPL)-like areas in spheroids were not distinguishable anymore. Similarly, photoreceptor rosettes and Müller radial glia were strongly decreased, whereas apoptosis was stimulated. The expression of transcripts for choline-acetyltransferase and muscarinic receptors was affected, revealing an effect of diazinon on the cholinergic system. This further proves the significance of cholinesterases and the cholinergic system for proper nervous system development and shows that further studies of debilitating diazinon actions on development are necessary.
Insights
Organophosphate pesticides like diazinon disrupt chick embryo retinal development, impairing neural structure and function. This highlights the critical role of acetylcholinesterase in nervous system development.
Area of Science:
- Neuroscience
- Developmental Biology
- Toxicology
Background:
- Developing embryos are highly susceptible to anticholinesterases, including organophosphorus pesticides.
- These agents can cause permanent neural development deficits.
- Acetylcholinesterase (AChE) plays a direct role in neuronal differentiation, warranting investigation into anticholinesterase developmental toxicity.
Purpose of the Study:
- To investigate the effects of the organophosphate diazinon on chick retinal differentiation in vitro.
- To assess diazinon's impact on neural structure, acetylcholinesterase activity, and gene expression in developing retinal cells.
Main Methods:
- Utilized an in vitro reaggregate approach with dissociated retinal cells from E6 chick embryos.
- Cultured retinal cell aggregates for 10 days with varying concentrations of diazinon (20-120 microM).
- Analyzed structural integrity, acetylcholinesterase activity, cell differentiation markers, apoptosis, and gene expression.
Main Results:
- Diazinon exposure reduced spheroid size and caused irregular outer surfaces.
- Significant inner structural distortions were observed, with loss of laminar organization.
- Acetylcholinesterase activity decreased, inner plexiform layer-like areas became indistinguishable, and photoreceptor rosettes/Müller glia were reduced.
- Apoptosis was stimulated, and expression of choline-acetyltransferase and muscarinic receptors was altered.
Conclusions:
- Diazinon significantly disrupts chick retinal differentiation in a dose-dependent manner.
- The findings underscore the importance of cholinesterases and the cholinergic system in nervous system development.
- Further research is necessary to understand the full scope of diazinon's detrimental effects on embryonic development.
