Figure 7

The progressive dilation of the central canal with time after spinal cord injury results in a loss of ependymal region cellular density. (A) Total ependymal region cell counts increase with enlarging central canal area up until a critical point. Thereafter, the absolute cell number decreases. (B) Cellular coverage of the central canal similarly decreases with enlarging central canal. Transverse toluidine blue stained sections of the adult rat spinal cord 450 days after injury demonstrating the evolution of the ependymal region cell changes are depicted in C-E. Mild (C) and moderate (D) central canal dilations are associated with an increasing ependymal region nuclear count. Large, aneurysmal dilation of the central canal (E) is accompanied by flattening of the ependymal cell layer, ependymal ciliary loss and disruptions in the continuity of cells lining the canal. Note the periependymal edema and gliosis, macrophage infiltration and loss of adjacent neuropil. Magnification = 60× for C-E.