Preferential recruitment of bone marrow-derived cells to rat palatal wounds but not to skin wounds.

OBJECTIVE

To investigate the contribution of bone marrow-derived cells to oral mucosa wounds and skin wounds.

BACKGROUND

Bone marrow-derived cells are known to contribute to wound healing, and are able to differentiate in many different tissue-specific cell types. As wound healing in oral mucosa generally proceeds faster and with less scarring than in skin, we compared the bone marrow contribution in these two tissues.

DESIGN

Bone marrow cells from GFP-transgenic rats were transplanted to irradiated wild-type rats. After recovery, 4-mm wounds were made in the mucoperiosteum or the skin. Two weeks later, wound tissue with adjacent normal tissue was stained for GFP-positive cells, myofibroblasts (a-smooth muscle actin), activated fibroblasts (HSP47), and myeloid cells (CD68).

RESULTS

The fraction of GFP-positive cells in unwounded skin (19%) was larger than in unwounded mucoperiosteum (0.7%). Upon wounding, the fraction of GFP-positive cells in mucoperiosteum increased (8.1%), whilst it was unchanged in skin. About 7% of the myofibroblasts in both wounds were GFP-positive, 10% of the activated fibroblasts, and 25% of the myeloid cells.

CONCLUSIONS

The results indicate that bone marrow-derived cells are preferentially recruited to wounded oral mucosa but not to wounded skin. This might be related to the larger healing potential of oral mucosa.