Cortical AAV-CNTF Gene Therapy Combined with Intraspinal Mesenchymal Precursor Cell Transplantation Promotes Functional and Morphological Outcomes after Spinal Cord Injury in Adult Rats

Figure 1

(a) Two AAV-CNTF^mCherry injections in the cerebral cortex. (b) BDA injections into the cortex revealed using immunoperoxidase; note the many labelled neurons in deeper layers. This animal had previously received cortical injections of AAV-CNTF^mCherry. (c–l) Longitudinal sections of the spinal cord—in all cases rostral is to the left of the picture. (c) Section immunostained for mCherry (red) and β-III tubulin (green) showing anterogradely labelled mCherry-positive axons (arrow) in the dorsal corticospinal tract far rostral to the lesion site. (d) Control AAV-GFP-injected rat (no MPCs injected); a small number of immunoperoxidase BDA-labelled axons and debris are visible just in front of a rostral cyst (arrow), with no axons extending beyond the injury. (e–g) Large numbers of mCherry-positive axons rostral (e, f) and running dorsally over and beyond the cyst (g); these rats received AAV-CNTF^mCherry cortical injections plus an intraspinal injection of viable rat mesenchymal precursor cells (rMPCs). Note in (e) the profusion of mCherry-positive profiles (large arrow) approximately 1 mm rostral to the lesion cavity, growing into regions dorsal to the corticospinal tract (small arrows). There appears to be considerable sprouting of axons in this zone (f). (h) Immunoperoxidase BDA-labelled axons and debris rostral to a cyst in a rat injected with AAV-CNTF^mCherry. Several axons can be seen running caudally, ventral to the cyst (arrows). (i) BDA-labelled cortical axons (arrows) visualized using a fluorescent secondary antibody (green), running over a cystic cavity. This animal also received AAV-CNTF^mCherry and viable MPC injections. (j–l) Cortical axons (arrows) double labelled (l) with both mCherry ((j), red) and BDA ((k), green); note, some axons are only mCherry or BDA immunoreactive. Scale bars: (a, e), 500 μm; (b, h, and i), 200 μm; (c, d, g, and j–l), 100 μm; and (f) 50 μm.