Thermal laser ablation with tunable lesion size reveals multiple origins of seizure-like convulsions in Caenorhabditis elegans

Anthony D Fouad,Angelica Du,Alice Liu,Priya D Bhirgoo,Christopher Fang-Yen

doi:10.1038/s41598-021-84516-y

Anthony D Fouad, Angelica Du + Show 3 more

Open Access

https://doi.org/10.1038/s41598-021-84516-y

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Journal: Scientific Reports	Publication Date: Mar 3, 2021
Citations: 3	License type: open-access

Affiliation: University of Pennsylvania

Abstract

Laser microsurgery has long been an important means of assessing the functions of specific cells and tissues. Most laser ablation systems use short, highly focused laser pulses to create plasma-mediated lesions with dimensions on the order of the wavelength of light. While the small size of the lesion enables ablation with high spatial resolution, it also makes it difficult to ablate larger structures. We developed an infrared laser ablation system capable of thermally lesioning tissues with spot sizes tunable by the duration and amplitude of laser pulses. We used our laser system in the roundworm C. elegans to kill single neurons and to sever the dorsal and ventral nerve cords, structures that are difficult to lesion using a plasma-based ablation system. We used these ablations to investigate the source of convulsions in a gain-of-function mutant for the acetylcholine receptor ACR-2. Severing the ventral nerve cord caused convulsions to occur independently anterior and posterior to the lesion, suggesting that convulsions can arise independently from distinct subsets of the motor circuit.

Highlights

Laser microsurgery has long been an important means of assessing the functions of specific cells and tissues
Compared with plasma-mediated ablation, our thermal ablation method has the advantage of a tunable lesion size through changes in the laser pulse duration and/or power, and can be used to lesion relatively large structures such as the ventral nerve cord without puncturing the cuticle
We performed thermal ablations in a worm in which the red fluorescent protein wCherry is expressed in a subset of ventral cord motor neurons via the transgene Pacr-2::wCherry

Summary

Introduction

Laser microsurgery has long been an important means of assessing the functions of specific cells and tissues. We used our laser system in the roundworm C. elegans to kill single neurons and to sever the dorsal and ventral nerve cords, structures that are difficult to lesion using a plasma-based ablation system. Compared with plasma-mediated ablation, our thermal ablation method has the advantage of a tunable lesion size through changes in the laser pulse duration and/or power, and can be used to lesion relatively large structures such as the ventral nerve cord without puncturing the cuticle. This method can create lesions throughout an adult animal, possibly because it is relatively insensitive to sample-induced optical aberrations

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Conclusion