Paving the Road for Coherent Anti-Stokes Raman Scattering (CARS) Imaging of Myelin

Abstract

Demyelinating diseases, such as multiple sclerosis (MS), result in the deterioration of the myelin sheath that covers the neural cells of the brain. A microscopy method that can be used to assess the effectiveness of therapeutics aimed at healing demyelinating diseases and to further study these diseases is needed. Specifically, a microscopy method with high specificity to myelin and low photobleaching of myelin is needed. Photobleaching is the fading of fluorescence after repeated cycles of excitation. Currently, fluorescence microscopy and similar methods that result in photobleaching and use dyes have been used to visualize the myelin. Dyes, however, stain tissue samples and may affect molecular functions. Besides these methods, coherent anti-Stokes Raman scattering (CARS) microscopy has also been used. In contrast to other used microscopy methods, CARS microscopy’s photobleaching can be minimized, and CARS microscopy does not use stains.

As an initial step toward investigating the ability of the CARS microscope to visualize different levels of myelin, which consists primarily of lipids, and to demonstrate CARS value for use in studying demyelinating diseases and in the development of therapeutic efficacy of drugs developed to treat MS; CARS imaging of lipid droplets in engineered adipose tissue was performed, and quantification and measurement of the lipid droplets was done. In addition, a mini incubation chamber for long-term in vitro imaging of demyelination was built, and a protocol for a demyelination study has been developed.