Table 1.
Overview of the number of mice included in experiments.
Figure 1.
Description of SCI, LPC and EAE models of spinal cord pathologies.
(A) Models of spinal cord pathologies. (B) Time course of mouse sacrifices. Day 0 is the time of contusion SCI, intraspinal injection of lysophosphatidylcholine (LPC) or PBS, or peripheral injection of EAE-inducing MOG/CFA/Pertussis toxin. Only SCI and LPC mice were sacrificed at days 1 and 3, due to the slow onset of EAE following immunization. (C) Spinal cord segments harvested for sectioning and analysis. The red arrow points to the lesion epicenter. (D) Gross histology of the low thoracic spinal cord following contusion SCI. Shown are representative examples of Luxol Fast blue (LFB)-stained sections taken from the Rostral segment (left column), Medial segment (middle column) and Caudal segment (right column) of a sham-operated mouse (sacrificed at day 21) and SCI mice at 3 and 14 days post-injury. Approximate distances (in millimeters) are shown from the lesion epicenter at the middle of the Medial segment (0). (E) Gross histology of the T9–10 thoracic spinal cord injection of PBS (upper panel) or LPC (lower panel) in the dorsolateral funiculus. Luxol Fast blue stains the white matter myelin, and reveals the large zone of demyelination already evident at 3 days after LPC injection. (F) Clinical scores and histopathology of EAE mice. Note the rapid increase in clinical scores between 1 and 21 days after immunization, reflecting declining locomotor function that stabilizes and slightly improves between 21 and 35 days after immunization (left). See Methods for description of clinical scores. Luxol Fast blue staining documented the presence of demyelinating plaques spread in the spinal cord white matter of EAE mice at 14 days post-immunization (right). Scale bars: D–F 100 µm.
Figure 2.
Distinct proliferative reactions in the spinal cord following SCI, LPC and EAE.
(A–E) Low magnification images of the spinal cord following immunohistochemistry for the cell proliferation marker Ki67 in a naive mouse (A), 7 days following contusion SCI (B), 7 days following intraspinal injection of PBS (C) or LPC (D), or 14 days following peripheral immunization in EAE mice (E). Scale bar: A–E, 80 µm.
Figure 3.
Changes in ependymal zone proliferation following contusion SCI.
(A) Immunohistochemistry for Ki67-positive (+) proliferating cells in each harvested segment of the spinal cord of naive mice and 3, 14, or 35 days post-injury (dpi). Sections are counterstained with cresyl violet. Note the increased cell proliferation in the ependymal zone of the Medial, Rostral and Cervical spinal cord segments in SCI mice compared to naive animals. (B) Multilabel fluorescence immunostaining of the ependymal zone at 7 dpi. Upper panel shows immunostaining for Vimentin (orange) and Ki67 (green) while lower panel shows the same field labeled with Olig2 (fucia) and Hoechst counterstaining (blue). Note that Vimentin+/Ki67+ proliferating EpCs can be seen leaving the central canal ependymal zone (arrowheads). (C) Graph of the spatial and temporal progression of changes in ependymal zone proliferation following contusion SCI. Scale bars: A, 40 µm; B, 35 µm.
Figure 4.
Ependymal cells do not proliferate in response to LPC and EAE models of demyelination.
Immunohistochemistry for Ki67-positive (+) ependymal zone cells in the Medial segment of mice injected intraspinally with PBS (left column) or lysophosphatidylcholine (LPC, middle column), or injected peripherally to induce EAE (right column). Images are from mice sacrificed 3, 7, 14, 21, or 35 days post injection/immunization (dpi). Scale bar = 35 µm.
Figure 5.
Comparison of spatiotemporal changes in ependymal proliferation after contusion SCI, intraspinal LPC injection or MOG immunization to induce EAE.
Complete summary of Ki67+ cell quantifications from the Cervical and three thoracic (Rostral, Medial, Caudal) segments of the spinal cord in all three models of spinal cord pathologies.