A Simple and Fast Optical Clearing Method for Whole-Mount Fluorescence In Situ Hybridization (FISH) Imaging

Area of Science:

• Biomedical Imaging
• Molecular Biology
• Microscopy Techniques

Background:

• Advanced microscopy requires specialized techniques for deep tissue imaging.
• Optical clearing methods improve light penetration and reduce scattering in biological samples.
• RNA fluorescence in situ hybridization (FISH) is crucial for visualizing gene expression.

Purpose of the Study:

• To develop a single-step optical clearing method compatible with RNA FISH.
• To simplify and optimize existing lipid-preserving refractive index matching for prolonged imaging depth (LIMPID) techniques.
• To enable high-resolution 3D imaging of whole-mount tissues using conventional fluorescence microscopes.

Main Methods:

• Developed a simplified, single-step optical clearing protocol (3D-LIMPID-FISH).
• Validated the method for co-labeling with antibody and RNA FISH probes.
• Custom-designed FISH probes for specific animal models (quail embryos).
• Utilized conventional fluorescence microscopy for 3D imaging.

Main Results:

• Achieved high-resolution, aberration-minimized 3D images of whole-mount tissues.
• Demonstrated compatibility with both antibody and FISH co-labeling.
• Successfully imaged quail embryos with custom FISH probes.
• Obtained high-quality 3D images without advanced microscopy equipment.

Conclusions:

• The optimized 3D-LIMPID-FISH protocol facilitates deep tissue 3D imaging with RNA FISH.
• The method is accessible, adaptable to various models, and compatible with standard fluorescence microscopes.
• This technique lowers the barrier for researchers to perform complex 3D biological imaging.