Inducing Targeted Neuronal Injury Using a High-Power Laser in a Drosophila Larva
JoVE Encyclopedia of Experiments
Neuroscience
0 views • 3:55 min • July 8th, 2025
Place an anesthetized Drosophila larva with its head-up on an oil drop on a glass slide containing vacuum grease spots.
Position a coverslip and gently press it to make contact with the larva.
Adjust the larva to expose the region containing the target neurons expressing fluorescent proteins.
Secure the slide on a two-photon microscope.
Use a low-power laser to minimize damage and scan the larva to locate the region with the fluorescent target neurons.
Next, adjust the scan window to focus on the target region containing axons, a type of neuronal projections.
Now, reduce the scan rate and increase the laser power.
The high-power laser will strike the targeted axons, generating localized heat that damages them and enhances fluorescence around the injury site.
Finally, switch back to low-power laser mode. The presence of small crater, ring-like structures at the injury site confirms successful neuronal injury.
Begin with anesthetizing the larvae. In a fume hood, place a 60 millimeter glass dish into a 15-centimeter plastic Petri dish. Then, fold a piece of tissue paper, and place it in the glass dish. Place the grape agar plate on the tissue after the diethyl ether is added. Next, onto a glass slide, place one drop of halocarbon 27 oil at the center, and place a spot of vacuum grease on each of the four corners.
Then, use forceps to transfer one larva onto the agar plate, and cover the glass dish to anesthetize the larva. As soon as the larva stops moving, carefully transfer it to the halocarbon oil with its head upright. Then, place a coverslip over the slide, and press it down gently, until it touches the larva. Next, use gentle force to slide the coverslip to roll the cells to be ablated to where the two photon laser will most easily hit them. The location will vary depending on what neurons are being targeted.
Now, secure the assembly on the two photon microscope stage, and focus on the cells of interest using a 40x oil immersion objective. In the software, switch to the scanning mode, and load the saved protocol. Make sure the pinhole is opened all the way. Then, in Live mode, get a good image of the region of interest. Next, stop the Live scan, so that the Crop button will become available. Using the Crop function, adjust the scan window to focus the target area on just the prospective site of injury.
Then open a new imaging window. Now, reduce the scan speed, and increase the laser intensity. Then toggle the continuous button to start and stop the scan. Watch carefully. As soon as there is a drastic increase in fluorescence, end the scan. Next, switch back to the original imaging window, and select the Live mode, and find the region that was just targeted by adjusting the focus.
A good indication of successful injury is the appearance of a small crater, ring-like structure, or localized debris right on the injury site. If the laser power was too high, a large damage area would be visible, which can be lethal.
Overview
This article describes a method for inducing localized neuronal injury in Drosophila larvae using two-photon microscopy. The procedure involves anesthetizing the larvae, positioning them on a slide, and using a laser to target specific axons, allowing for the study of neuronal responses to injury.
Key Study Components
Area of Science
- Neuroscience
- Imaging Techniques
- Neuronal Injury
Background
- Drosophila larvae are commonly used in neuroscience research.
- Two-photon microscopy allows for precise targeting of neuronal structures.
- Understanding neuronal injury mechanisms is crucial for neuroscience.
- Localized injury can help study neuronal repair processes.
Purpose of Study
- To develop a reliable method for inducing neuronal injury.
- To observe the effects of injury on neuronal structures.
- To enhance understanding of neuronal responses to damage.
Methods Used
- Anesthetization of Drosophila larvae using diethyl ether.
- Placement of larvae on a glass slide with halocarbon oil.
- Use of two-photon microscopy to target axons with a laser.
- Monitoring fluorescence changes to confirm injury.
Main Results
- Successful induction of localized neuronal injury was achieved.
- Fluorescence increased significantly at the injury site.
- Small crater-like structures confirmed the injury.
- Method demonstrated reproducibility for future studies.
Conclusions
- The method provides a valuable tool for studying neuronal injury.
- Findings contribute to the understanding of neuronal repair mechanisms.
- Future research can build upon this technique to explore further neuronal responses.
Frequently Asked Questions
Executive Industry Relevance
Targeted neuronal injury in Drosophila larvae using high-power laser microscopy enables precise interrogation of neuroregeneration mechanisms in vivo. This model supports early-stage discovery by providing a controlled system for evaluating neuronal response to injury, critical for de-risking neurotherapeutic targets. The approach enhances predictive confidence in translational neuroscience pipelines by enabling reproducible, quantitative injury induction and assessment.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Enables mechanistic interrogation of neuronal injury and repair pathways in a genetically tractable model.
- Supports biological de-risking by allowing direct observation of neuronal response to controlled damage.
- Facilitates functional target validation through reproducible induction and quantification of injury.
Screening & Assay Development
- Provides a validated in vivo system for downstream screening of neuroprotective or regenerative compounds.
- Standardizes injury induction and readout, supporting assay reproducibility and quantitative analysis.
- Enables reliable evaluation of compound effects on neuronal repair processes.
Translational & Preclinical Research
- Aligns with disease-relevant mechanisms by modeling neuronal injury and regeneration in a whole-organism context.
- Supports continuity from discovery to preclinical validation by enabling longitudinal studies of neuronal recovery.
- Offers predictive de-risking for neuroregeneration targets prior to mammalian model investment.
Pipeline & Workflow Integration
This method integrates at the interface of early discovery and preclinical research, bridging target validation and lead identification for neuroregeneration programs.
- Discovery Biology: Supports hypothesis testing on neuronal injury response and pathway involvement.
- Screening: Delivers standardized, reproducible injury induction for compound evaluation workflows.
- Analytics: Provides quantitative fluorescence and morphological readouts for comparative analysis.
- Translational Research: Enables assessment of regenerative capacity in a disease-relevant in vivo system.
- Enterprise Reuse: Establishes a reusable platform for diverse neurobiology and neuroregeneration studies.
Operational & Enterprise Impact
- Scientific Value: Increases predictive confidence and reduces mechanistic ambiguity in neuroregeneration research.
- Operational Value: Enhances standardization, reproducibility, and scalability of neuronal injury assays.
- Strategic Value: Informs go/no-go decisions and reduces late-stage biological risk in neurotherapeutic pipelines.
- Portfolio Impact: Supports risk-adjusted prioritization and advancement of neuroregeneration targets.
Implementation Considerations
- Requires expertise in two-photon microscopy and Drosophila handling.
- Demands access to advanced imaging infrastructure and precise laser control.
- Necessitates cross-team standardization of injury induction and readout protocols.
- Adaptation may be needed for different neuronal subtypes or developmental stages.
- Careful calibration of laser power is essential to avoid excessive or lethal damage.
Biopharma FAQs
Facial Nerve Surgery in the Rat Model to Study Axonal Inhibition and Regeneration
Related Videos
0 Views
Laser-Induced Brain Injury in the Motor Cortex of Rats
Related Videos
0 Views
Modified Spared Nerve Injury Surgery Model of Neuropathic Pain in Mice
Related Videos
0 Views
In vivo Laser Axotomy in C. elegans
Related Videos
0 Views
Two-Photon Laser-Induced Neural Injury: A Method to Observe Axon Degeneration and Regeneration in Drosophila Larvae
Related Videos
0 Views
Two-Photon Laser Axotomy: A Method to Injure Axons in Zebrafish Embryos and Observe Axonal Recovery
Related Videos
0 Views
Mechanically Injuring Drosophila Larvae Segmental Nerves to Induce Neurodegeneration
Related Videos
0 Views
Inducing Penetrating Traumatic Brain Injury in Adult Drosophila Flies
Related Videos
0 Views
Selective Single-Neuron Laser Ablation in a Zebrafish Larva Using a Confocal Microscope
Related Videos
0 Views
Targeted Neuronal Ablation Using Two-Photon Microscopy in a Zebrafish Larava
Related Videos
0 Views
Last updated: 22 August 2026