Figure 7.
Chronic transplantation of hESC-derived OPCs resulted in no change in the density of oligodendrocyte remyelination or locomotor recovery compared with controls. a, Toluidine blue-stained transverse section from a transplanted animal, illustrating very sparse remyelination among normally myelinated and demyelinated axons, and increased extracellular space. b, Electron micrograph of the transplant environment at 10 months after injury, illustrating that demyelinated axons (*) were present. c, Electron micrograph of the transplant environment at 10 months after injury, illustrating axons surrounded by enlarged intermediate filament-rich astrocytic processes (AP), which occupied virtually all of the extracellular space. d, Electron micrograph of the transplant environment at 10 months after injury, illustrating an astrocyte (a) with a large intermediate filament-rich process (AP) extending to demyelinated axons surrounded by intermediate filament-rich astrocytic processes (arrows) and myelinated axons surrounded by intermediate filament-rich astrocytic processes (arrowheads). e, Quantification of normally myelinated, demyelinated, and oligodendrocyte or Schwann cell-remyelinated axons in hESC-derived OPC transplanted, and DMEM-injected animals. Error bars illustrate SD. The myelin sheath thickness for each class of axons is indicated in brackets. f-h, The degree of locomotor recovery in animals that received 1.5 million cell transplants was not significantly (p > 0.1) different from those that received vehicle-only injections, regardless of the severity of injury. Magnification: a, 400×; b-d, 3000×.