Embryonic stem (ES) cells have been investigated in repair of the CNS following neuronal injury and disease; however, the efficacy of these cells in treatment of postinjury
pain is far from clear. In this study, we evaluated the therapeutic potential of predifferentiated mouse ES cells to restore sensory deficits following
spinal cord injury (SCI) in mice. The
pain model used unilateral
intraspinal injection of
quisqualic acid (QUIS) into the dorsal horn between vertebral levels T13 and L1. Seven days later, 60,000 predifferentiated ES cells or media were transplanted into the site of the lesion. Histological analysis at 7, 14, and 60 days post-
transplantation revealed that animals receiving ES cell transplants suffered significantly less tissue damage than animals receiving media alone. Transplanted cells provided immediate effects on both spontaneous and evoked
pain behaviors. Treatment with ES cells resulted in 0% (n = 28) excessive grooming behavior versus 60% (18 of 30) in media-treated animals. In the
acetone test (to assess
thermal allodynia), mice recovered to preinjury levels by 12 days after ES cell transplant, whereas control animals injected with media after SCI did not show any improvement up to 60 days. Similarly, the von Frey test (to assess
mechanical allodynia) and the
formalin test (to assess nociceptive
hyperalgesia) showed that
transplantation of predifferentiated ES cells significantly reduced these
pain behaviors following injury. Here we show that predifferentiated ES cells act in a neuroprotective manner and provide antinociceptive and
therapeutic effects following excitotoxic SCI.