In vivo imaging and quantitative analysis of changes in axon length using transgenic zebrafish embryos

Area of Science:

• Neuroscience
• Developmental Biology
• Pharmacology

Background:

• Axon development is critical for nervous system function.
• Ethanol exposure during development can negatively impact neuronal structure.
• Accurate measurement of axon length is essential for assessing neurotoxicity and developmental effects.

Purpose of the Study:

• To establish and validate an in vivo imaging procedure for measuring axon length in zebrafish embryos.
• To assess the impact of ethanol exposure on motor neuron axon length using this novel imaging technique.
• To demonstrate the utility of this method for high-throughput compound screening.

Main Methods:

• Automated fluorescent image acquisition using ImageXpress Micro high content screening reader.
• Axon length analysis performed with AcuityXpress software and Neurite Outgrowth Application module.
• Treatment of transgenic [hb9:GFP] zebrafish embryos with ethanol (2-2.5%) at 28 hours post-fertilization.

Main Results:

• High-dose ethanol treatment significantly reduced average axon lengths in zebrafish embryos compared to controls.
• No significant difference in axon lengths was observed between embryos incubated at 22°C and 28.5°C.
• The imaging procedure proved effective for time-efficient assessment of axon development.

Conclusions:

• The developed imaging procedure is a robust method for quantifying axon length in vivo.
• Ethanol exposure during early development impairs motor neuron axon elongation in zebrafish.
• This assay system enables efficient screening of compounds for neurodevelopmental toxicity.