Fig. 6
Pathology of the area postrema and medulla oblongata. Immunostaining of AQP4 in a sagittal section of the brain of a rat that had received an injection of hIgGcont (a) and a schema of the sagittal rat brainstem (b). In the 1 mg E5415A group, there were several AQP4-lacking lesions with a longitudinally extended moniliform appearance, from the obex and the area postrema to the upper cervical cord (c). Compared with injection of hIgGcont (a), the marked loss of AQP4 was observed in the area postrema and the obex (b). Immunostaining for GFAP was weak at the area postrema and in multiple perivascular lesions (d) around Iba1-positive vessels (e). Furthermore, medulla oblongata lesions demonstrated typical NMO pathology, including extensive loss of AQP4 (f), EAAT2 (g), and GFAP (h) at Iba1-positive perivascular regions (i), but the myelin sheath (j) and neurofilament (k) were relatively preserved. Scale bar = 300 μm