Early necrosis and apoptosis of Schwann cells transplanted into the injured rat spinal cord

Authors

  • Caitlin E. Hill,

    1. The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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  • Andres Hurtado,

    1. The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
    2. The International Center for Spinal Cord Injury, Kennedy Krieger Institute and the Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MA 21205, USA
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  • Bas Blits,

    1. The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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  • Ben A. Bahr,

    1. Department of Pharmaceutical Sciences, Neuroscience Program, University of Connecticut, Storrs, CT 06269, USA
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  • Patrick M. Wood,

    1. The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
    2. Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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  • Mary Bartlett Bunge,

    1. The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
    2. Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL 33136, USA
    3. Department of Anatomy and Cell Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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  • Martin Oudega

    1. The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
    2. The International Center for Spinal Cord Injury, Kennedy Krieger Institute and the Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MA 21205, USA
    3. Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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Dr C.E. Hill, as above.
E-mail: chill@miamiproject.med.miami.edu

Abstract

Poor survival of cells transplanted into the CNS is a widespread problem and limits their therapeutic potential. Whereas substantial loss of transplanted cells has been described, the extent of acute cell loss has not been quantified previously. To assess the extent and temporal profile of transplanted cell death, and the contributions of necrosis and apoptosis to this cell death following spinal cord injury, different concentrations of Schwann cells (SCs), lentivirally transduced to express green fluorescent protein (GFP), were transplanted into a 1-week-old moderate contusion of the adult rat thoracic spinal cord. In all cases, transplanted cells were present from 10 min to 28 days. There was a 78% reduction in SC number within the first week, with no significant decrease thereafter. Real-time polymerase chain reaction showed a similar 80% reduction in GFP-DNA within the first week, confirming that the decrease in SC number was due to death rather than decreased GFP transgene expression. Cells undergoing necrosis and apoptosis were identified using antibodies against the calpain-mediated fodrin breakdown product and activated caspase 3, respectively, as well as ultrastructurally. Six times more SCs died during the first week after transplantation by necrosis than apoptosis, with the majority of cell death occurring within the first 24 h. The early death of transplanted SCs indicates that factors present, even 1 week after a moderate contusion, are capable of inducing substantial transplanted cell death. Intervention by strategies that limit necrosis and/or apoptosis should be considered for enhancing acute survival of transplanted cells.

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