Real-Time CARS Imaging Reveals a Calpain-Dependent Pathway for Paranodal Myelin Retraction during High-Frequency Stimulation

摘要: High-frequency electrical stimulation is becoming a promising therapy for neurological disorders, however the response of central nervous system to remains poorly understood. The current work investigates myelin by laser-scanning coherent anti-Stokes Raman scattering (CARS) imaging in live spinal tissues real time. Paranodal retraction at nodes Ranvier was observed during 200 Hz stimulation. Retraction seen begin minutes after onset and continue up 10 min ceased, but found reverse 2 h recovery period. resulted exposure Kv 1.2 potassium channels visualized immunofluorescence. Accordingly, treating stimulated tissue with channel blocker, 4-aminopyridine, led appearance shoulder peak compound action potential curve. Label-free CARS coupled multiphoton fluorescence immuno-labeled proteins revealed that high-frequency induced paranodal via pathologic calcium influx into axons, calpain activation, cytoskeleton degradation through spectrin break-down.