Figure 4.
Inhibition of AQP4 Expression and Subcellular Relocalization after Cytotoxic Edema In Vivo Improves Electrophysiological, Sensory and Locomotor Functional Recovery, BSCB Breakdown, and Spinal Cord Cavitation
(A) Superimposed representative spinal cord compound action potential (CAP) traces demonstrating the significant functional improvement in CaMi-treated (TFP) and PKAi-treated (H89) rats compared with vehicle-treated and PKCi-treated (Gö 6983) rats following DC crush. CaMi treatment was 41 mM TFP. PKAi treatment was 10 mM H89. PKCi treatment was 9.94 μM Gö 6983. In all cases, these were injected directly into the lesion site at a volume of 2.5 μL.
(B and C) CaMi and PKAi significantly improved the mean CAP area (B) and the mean CAP amplitude (C).
(D) CaMi and PKAi treatment significantly improved the hindpaw tape sensing and removal time, and within 2 weeks, CaMi-treated and PKAi-treated rats recovered completely and were indistinguishable from sham controls.
(E) The mean ratio of slips/total steps in a ladder-crossing test was significantly improved after CaMi and PKAi treatment, returning to sham control levels by 2 weeks. For the tape sensing/removal and ladder crossing tests, significant deficits remained in vehicle-treated and PKCi-treated rats. #p < 0.05, linear mixed model; ##p < 0.05, generalized linear mixed model; calculated as described previously (Fagoe et al., 2016; Table S2; n = 6 rats/group; 3 independent repeats; total n = 18 rats/group).
(F) Treatment with 41 mM TFP significantly reduced BSCB breakdown 7 days after DC crush (right panel), as determined by albumin staining (green) around the lesion site (representative images are shown in the left panel). ∗p < 0.05 (Table S2) by ANOVA followed by t test with Bonferroni correction.
(G) TFP also suppressed the normal process of cavitation that occurs at lesion sites after DC crush, significantly reducing the cavity area 6 weeks after DC crush at all depths through the DC (right panel; black-filled dots represent DC+vehicle; white dots represent DC+CaMi), as determined by laminin staining (brown) (representative images are shown in the left panel). n = 6 rats/group; 2 independent repeats (total n = 12 rats/group); p = 4.0 × 10−10, comparing lesion volume in DC+vehicle with DC+CaMi by t test (Table S2).