Epithelialization in oral mucous wound healing in terms of energy metabolism

The purpose of this study was to clarify the "healing capacity" of wounds of the oral mucosa in comparison to those of the skin, and to evaluate the wound healing mechanism of oral mucosa using a cytobiological approach from the aspect of energy metabolism in oral keratinocytes.

Samples of epidermal and oral keratinocytes collected at surgery and of cultured oral keratinocytes were used to analyze (1) by gas chromatography the composition of fatty acids (16:0, 18:2, 20:4) in the cell membranes of keratinocytes, (2) by immunohistochemical staining of GLUT-1 antibody and specific PAS staining the localization of glucose metabolism, and (3) by RT-PCR and Western blotting the expression of GLUT-1 mRNA and of protein in the keratinocytes of the basal and parabasal layers of each epithelial tissue.

1. The % composition of palmitic acid (16:0) was significantly higher in buccal mucosal keratinocytes (27.18+/-3.74%) and in the gingiva (23.00+/-1.40%) than in the epidermis (17.54+/-0.37%). 2. Immunohistochemical staining showed GLUT-1 protein in the skin to be expressed only in the bulge region of hair follicles and in the epidermal basal layer, and observed nearly throughout all epithelial cell layers in the oral mucosa. 3. PAS-positive cells were observed among differentiation-enhanced cells in the upper prickle layer in the oral mucosa. 4. The same results were obtained from RT-PCR and a Western blotting analysis.

The present study demonstrated definite cytobiological evidence that the oral mucosa surpasses the skin in regard to its wound healing capacity.