The unmyelinated axons are uncovered or with no myelin sheath while myelinated axons are covered with a myeline sheath of lipid. In case of demyelinated axons under some pathological conditions you can observe damage or loss of myeline sheath some at places.

Hello Nicolas. H&E staining isn't the best option for differentiation of axons, given that H&E does not stain axons at all. H&E stains nuclei and cytoplasm of neuroglia, but not axons. Therefore, I would recommend usage of other histological stains for myelin such as Sudan Black B or Luxol Fast Blue or Oil Red. When there is a demyelination, you will notice a loss of staining in that area, while axons with no myelin wont be stained at all in both control and treated group. Here is a DOI 10.1038/s41598-017-02638-8 where you can find micrographs and brief protocols.

Best regards,

Milorad

Nicolas Valencia Diaz H&E is not the right stain for your purpose. Instead you should try Kluver-Barrera stain, which combines Luxol Fast Blue and Cresyl Violet. Cresyl Violet will stain the neuronal soma pink, and Luxol Fast Blue will stain myelin blue. That way you can distinguish localized demyelination more easily. Here's a protocol: https://www.emsdiasum.com/microscopy/technical/datasheet/26681.aspx

Thank you very much for your answers! I appreciate all your help! Sarah Hellewell Milorad Dragic Manju Tembhre