OBJECTIVETo investigate the expression and its significance of melatonin receptor in human hypertrophic scarring.

METHODSThe expression of melatonin receptor GPR50 was detected with immunohistochemistry and the melatonin receptors (MT1, MT2) mRNA were assessed with RT-PCR method in 10 cases of human hypertrophic scar and normal skin. The positive production was sequenced with auto sequencing instrument.

RESULTSPositive signals of melatonin receptor could be found in the cell membrane and cytoplasm. The melatonin receptor GPR50 was located in the epithelial basal cells,sweat gland cells and hair follicle in both hypertrophic scar and normal skin. The melatonin receptor GPR50 was extensively expressed in fibroblasts of hypertrophic scar, but not in fibroblasts in normal skin. RT-PCR showed that the expression of melatonin receptor (MT1, MT2) mRNA in hypertrophic scar was significantly higher than that in normal skin (P < 0.05). In normal skin and hypertrophic scar group, the expression of MT1 mRNA was higher than MT2 mRNA (P < 0.05). In normal skin and hypertrophic scar group, the expression of MT1 mRNA was 0.99081 +/- 0.26485 and 1.16584 +/- 0.21829 copy number/microl cDNA, respectively; the expression of MT2 mRNA was 0.77083 +/- 0.15927 and 0.99550 +/- 0.14624 copy number/ microl cDNA, respectively. Sequencing results indicated that the positive product coincided with cDNA of human melatonin receptor in GeneBank.

CONCLUSIONSPositive expression of melatonin receptor can be found in human hypertrophic scar and normal skin, but it is higher in scar. The over expression of melatonin receptor in hypertrophic scar may be related to the development of hypertrophic scar.