Increased SPARC accumulation during corneal repair

Exp Eye Res. 2003 Jul;77(1):85-92. doi: 10.1016/s0014-4835(03)00060-5.


Keratocytes can become fibroblasts and myofibroblasts during corneal injury and wound healing. We used the in vitro bovine keratocyte repair model system, which involves culturing collagenase-isolated keratocytes in serum-free media and then adding serum or serum plus TGF-beta to the culture media to induce the fibroblast and myofibroblast phenotypes, respectively, to evaluate the synthesis of secreted products by the cells. Serum and serum plus TGF-beta rapidly induced the fibroblast morphology and alpha smooth muscle actin, a marker of myofibroblasts. Keratocytes cultured in serum and serum plus TGF-beta also increased the synthesis of several high molecular weight products (approximately 100kD and larger) and the accumulation of a 43kD protein shown to be osteonectin/SPARC by both sequencing tryptic peptides from the protein and by reaction with antisera to osteonectin/SPARC. Immunohistochemical staining of mouse corneas with antisera to SPARC seven days post-wounding also demonstrated an increased accumulation of SPARC in the regions undergoing repair. These results indicate SPARC accumulation is a marker for stromal repair.

MeSH terms

  • Animals
  • Biomarkers / analysis
  • Blotting, Western / methods
  • Cattle
  • Cells, Cultured
  • Cornea / metabolism*
  • Cornea / pathology
  • Corneal Ulcer / metabolism*
  • Corneal Ulcer / pathology
  • Electrophoresis, Polyacrylamide Gel
  • Extracellular Matrix
  • Immunohistochemistry / methods
  • Keratinocytes / chemistry
  • Lymphotoxin-alpha / pharmacology
  • Mice
  • Osteonectin / analysis*
  • RNA, Messenger / analysis
  • Reverse Transcriptase Polymerase Chain Reaction
  • Wound Healing*


  • Biomarkers
  • Lymphotoxin-alpha
  • Osteonectin
  • RNA, Messenger