Fig 1: Axonal damage and loss in the spinal cord and optic nerve of the NMO-rat. a Axon injury detected in the NMO-rat compared to the Control-rat (rats infused with IgGAQP4+2 and IgGControl2, D7) using neurofilament immunostaining: reduced number of axons detected as NF-M-positive spots in the white matter (WM); fragmentation and reduced axon thickness in the gray matter (GM). b Classification (10–20 to 100–140 µm2, ImageJ) and quantification (mean by field) of NF-M-positive spots in the spinal cord of the NMO-rats (n = 6) compared to the Control-rats (n = 6): loss of axons with 60–140 µm2 sections in the NMO-rats (in cart: evaluation of the total axon number, p = 0.03). c Co-detection of myelin alteration (MBP in green) and axonal loss (neurofilament NF-M subtype in red) in the spinal cord of the NMO-rat compared to the Control-rat. d Increased expression of the NF-H phosphorylated form, a marker of axon injury, detected by Western blot (pNF-H/NF-H ratio; p = 0.04). e Axon fragmentation and loss in the optic nerve of the NMO-rats compared to the Control-rat detected by NF-M immunostaining. Scale bars = 20 µm