In vivo fluorescence imaging of muscle cell regeneration by transplanted EGFP-labeled myoblasts

Mol Ther. 2010 Apr;18(4):835-42. doi: 10.1038/mt.2010.3. Epub 2010 Feb 2.

Abstract

In vivo fluorescence imaging (FLI) enables monitoring fluorescent protein (FP)-labeled cells and proteins in living organisms noninvasively. Here, we examined whether this modality could reach a sufficient sensitivity to allow evaluation of the regeneration process of enhanced green fluorescent protein (eGFP)-labeled muscle precursors (myoblasts). Using a basic FLI station, we were able to detect clear fluorescence signals generated by 40,000 labeled cells injected into a tibialis anterior (TA) muscle of mouse. We observed that the signal declined to approximately 25% on the 48 hours of cell injection followed by a recovery starting at the second day and reached a peak of approximately 45% of the original signal by the 7th day, suggesting that the survived population underwent a limited run of proliferation before differentiation. To assess whether transplanted myoblasts could form satellite cells, we injured the transplanted muscles repeatedly with cardiotoxin. We observed a recovery of fluorescence signal following a disappearance of the signal after each cardiotoxin injection. Histology results showed donor-derived cells located underneath basal membrane and expressing Pax7, confirming that the regeneration observed by imaging was indeed mediated by donor-derived satellite cells. Our results show that FLI is a powerful tool that can extend our ability to unveil complicated biological processes such as stem cell-mediated regeneration.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cardiotoxins / adverse effects
  • Cell Differentiation
  • Cell Proliferation
  • Green Fluorescent Proteins / analysis
  • Green Fluorescent Proteins / genetics
  • Mice
  • Mice, Inbred C57BL
  • Mice, SCID
  • Microscopy, Fluorescence / methods*
  • Muscle, Skeletal / cytology
  • Muscle, Skeletal / injuries
  • Muscle, Skeletal / physiology*
  • Myoblasts / transplantation*
  • PAX7 Transcription Factor / physiology
  • Regeneration*
  • Satellite Cells, Skeletal Muscle / physiology

Substances

  • Cardiotoxins
  • PAX7 Transcription Factor
  • PAX7 protein, human
  • enhanced green fluorescent protein
  • Green Fluorescent Proteins