Quantum mechanics

Solvatochromism

Neuroscience

Biology

Myelin sheath

Biochemistry

Solvent

Electron microscope

White matter

Radiology

Immunology

Physics

Nile red

Optics

Central nervous system

Fluorescence

Pathological

Polarity (international relations)

Myelin

Multiple sclerosis

Medicine

Chemistry

Cell

Biophysics

Magnetic resonance imaging

Pathology

Proceedings of the National Academy of Sciences

Significance Many diseases of the nervous system affect white matter and myelin, the critical lipid-rich insulating material enveloping axons. We report a method based on solvatochromic fluorescent probes and spectral microscopy that detects very early pathological changes in myelin in both a rodent model and in postmortem human multiple sclerosis brain at a stage that precedes overt histological myelin loss. Our method reveals that multiple sclerosis white matter exhibits widespread changes in myelin dielectric constant in areas distant from typical inflammatory demyelinating lesions. Fluorescence spectroscopy using solvatochromic lipid probes such as Nile Red has the ability to report, with high sensitivity and in a quantitative manner, early physicochemical changes in cells and tissues that precede pathological alterations detectable by conventional histological methods.

Nile Red fluorescence spectroscopy reports early physicochemical changes in myelin with high sensitivity