Figure 8.

Colocalization of C1q, fluoromyelin and APP in the spinal cord of TMEV-IDD and rEAE mice. TMEV-IDD and rEAE mice were necropsied at ~120 dpi (chronic stage) and ~15 dpimm (acute relapse), respectively. Spinal cords were harvested for immunohistochemical analyses of the complement component C1q (A, M, D, P, G, S, J, V), the myelin marker fluoromyelin red (B, E, H, K) and the axonal damage marker APP (N, Q, T, W). Age-matched sham controls show no apparent C1q staining (A, D, M, P), as well as no demyelination (B, E) or APP deposits (N, Q). In TMEV-IDD, C1q staining (green in G, S) is observed in regions lacking fluoromyelin staining (red in I), i.e., demyelination and areas enriched of APP deposits (red in U), confirming an association between the activation of the classical pathway and CNS damage. In contrast, in rEAE, we found that C1q (green in J, V) does not colocalize with either demyelination (red in L) or axonal damage (red in X), suggesting that, in these mice, the activation of the classical pathway is not directly involved in CNS injury. Merge of C1q and fluoromyelin (C, F, I, L) and C1q and APP (O, R, U, X) is shown with DAPI (blue) for clarity of nucleus localization. Insets in images show white boxed areas at higher magnification. In (G–L), areas of demyelination are demarcated by a solid white line. Images are representative of 4 to 5 mice per group. Representative z stacks are shown and the scale bar = 100μM.