In vivo imaging of single axons in the mouse spinal cord
We provide a protocol that describes imaging of single fluorescently labeled axons in the spinal cord of living mice. This method takes advantage of transgenic mouse lines in which the thy1-promoter drives the expression of variants of the green fluorescent protein in a small percentage (less than 1%) of sensory neurons. As a consequence, single axons can be resolved in the surgically exposed dorsal column using wide-field epifluorescence microscopy. This approach allows direct observation of axonal degeneration and regeneration in mouse models of spinal cord pathology for several hours or repetitively over the course of several days.