Abstract
Purpose :
Ocular pathologies are the most common sensory impairments that greatly impact quality of life. While direct consequences of the pathologies can now be followed using cutting-edge in vivo imaging, the cellular causes and degeneration of these pathologies still call for histological studies. These studies are currently restricted when trying to reach nanoscale resolution by the availability of rare and expansive microscopes (such as electron or bi-photon microscope).
We recently implemented in the team an innovative histological technic called Expansion Microscopy (ExM). This technique, based on physical, isotropic expansion of tissues, allows nanoscale imaging of biological specimens with conventional microscopes.
Here, we describe the first use of this technique in the human retina, to visualize and render in 3D the anatomy of retinal cells in physiological and pathological conditions.
Methods :
Retinas were isolated and fixated in paraformaldehyde, before performing immunohistochemistry. Samples were embedded in an acrylamide gel to which fluorophores were anchored. The tissue was then enzymatically digested, expanded in water and imaged using either confocal or light-sheet fluorescent microscopy.
Results :
Thanks to the nanoscale resolution allowed by this technique, we were able to study in 3D for example the anatomy of physiological and pathological cones photoreceptors, from opsin migration to the structural deformation of photoreceptors retinal layer.
Conclusions :
By implementing ExM in the eye, this project made subcellular study easily accessible, thus broadening the field of possible nanoscale studies in ocular pathologies.
This is a 2021 ARVO Annual Meeting abstract.