In vivo coherent anti-Stokes Raman scattering microscopy reveals vitamin A distribution in the liver

Here we present a microscope setup for coherent anti-Stokes Raman scattering (CARS) imaging, devised to specifically address the challenges of in vivo experiments. We exemplify its capabilities by demonstrating how CARS microscopy can be used to identify vitamin A (VA) accumulations in the liver of a living mouse, marking the positions of hepatic stellate cells (HSCs). HSCs are the main source of extracellular matrix protein after hepatic injury and are therefore the main target of novel nanomedical strategies in the development of a treatment for liver fibrosis. Their role in the VA metabolism makes them an ideal target for a CARS-based approach as they store most of the body's VA, a class of compounds sharing a retinyl group as a structural motive, a moiety that is well known for its exceptionally high Raman cross section of the CC stretching vibration of the conjugated backbone.

Automated summary

The microscope setup presented in this study is tailored to address challenges in in vivo experiments, showcasing its use in identifying vitamin A accumulations in the liver and marking the positions of hepatic stellate cells. These cells, being the main source of extracellular matrix protein after hepatic injury, are key targets for novel nanomedical strategies in liver fibrosis treatment and their role in vitamin A metabolism makes them ideal for a CARS-based approach.