Bone marrow-derived cells in palatal wound healing.
OBJECTIVE
Myofibroblasts are responsible for contraction and scarring after cleft palate repair. This leads to growth disturbances in the upper jaw. We hypothesized that cells from the bone marrow are recruited to palatal wounds and differentiate into myofibroblasts.


METHODS
We transplanted bone marrow from green fluorescent protein (GFP)-transgenic rats into lethally irradiated wild-type rats. After recovery, experimental wounds were made in the palatal mucoperiosteum, and harvested 2 weeks later. GFP-expressing cells were identified using immunostaining. Myofibroblasts, activated fibroblasts, endothelial cells, and myeloid cells were quantified with specific markers.


RESULTS
After transplantation, 89 ± 8.9% of mononuclear cells in the blood expressed the GFP and about 50% of adherent cells in the bone marrow. Tissue obtained during initial wounding contained only minor numbers of GFP-positive cells, like adjacent control tissue. Following wound healing, 8.1 ± 5.1% of all cells in the wound area were positive, and 5.0 ± 4.0% of the myofibroblasts, which was significantly higher than in adjacent tissue. Similar percentages were found for activated fibroblasts and endothelial cells, but for myeloid cells it was considerably higher (22 ± 9%).


CONCLUSIONS
Bone marrow-derived cells contribute to palatal wound healing, but are not the main source of myofibroblasts. In small wounds, the local precursor cells are probably sufficient to replenish the defect.
Verstappen
J
J
Department of Orthodontics and Oral Biology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Katsaros
C
C
Torensma
R
R
Von den Hoff
J W
JW
D000818:Animals; D015415:Biomarkers / Q000032:analysis; D001854:Bone Marrow Cells / Q000502:physiology*; D016026:Bone Marrow Transplantation / Q000379:methods; D002452:Cell Count; D002454:Cell Differentiation / Q000502:physiology; D002465:Cell Movement / Q000502:physiology; D042783:Endothelial Cells / Q000502:physiology; D005347:Fibroblasts / Q000502:physiology; D049452:Green Fluorescent Proteins; D007958:Leukocyte Count; D007963:Leukocytes, Mononuclear / Q000502:physiology; D049408:Luminescent Agents; D022423:Myeloid Cells / Q000502:physiology; D058628:Myofibroblasts / Q000502:physiology*; D010159:Palate / Q000293:injuries* / Q000473:pathology; D010521:Periosteum / Q000293:injuries / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D055647:Rats, Transgenic; D019172:Transplantation Conditioning; D014916:Whole-Body Irradiation; D014945:Wound Healing / Q000502:physiology
D015415:Biomarkers; D049408:Luminescent Agents; D049452:Green Fluorescent Proteins