Fig. 1.

Paranodal disruption occurs early in response to hypoperfusion in the corpus callosum. (A and B) Colocalization of axonal CASPR and glial Neurofascin protein indicates intact septate-like junctions at the paranodes in the sham group. In response to hypoperfusion, at both 3 days and 1 month, there is a selective loss of Neurofascin co-localisation with CASPR which is indicative of a disruption of the paranodes, scale bar = 1 μm. (E) The overlap coefficient after Manders, which is insensitive to differences in signal intensities between the two channels, shows significant loss in colocalization after 3 days and 1 month of hypoperfusion (3 days sham n = 13, hypoperfusion n = 12; 1 month sham n = 9, hypoperfusion n = 9). Analysis was conducted in the corpus callosum. *, P < 0.05, **, P < 0.005 (unpaired t-test, two-tailed). (D) There is a non-significant increase in the number of paranodes disrupted at 3 days hypoperfusion (n = 5) as compared to shams (n = 5) which is significant at 1 month after hypoperfusion (n = 4) as compared to shams (n = 6). Analysis was conducted in the corpus callosum. *, P < 0.05 (unpaired t-test, two-tailed). (C) Electron micrographs show paranodal disruption in response to hypoperfusion in the optic nerve. Arrows = axonal membrane at the paranodal region, asterix = paranodal loop. Disruption of septate-like junctions indicated by loss of transverse bands, scale bars = 0.1 μm. (F) A significant increase in paranodes without septate-like junctions was observed after 1 month of hypoperfusion *, P < 0.05 (unpaired t-test, two-tailed).