OBJECTIVETo explore the change of gene expression of extracellular-signal regulated protein kinase 5 (ERK5) and its upstream signaling molecule (MEK5) in fetal skin of differentially developmental stages and hypertrophic scars.

METHODSAfter morphological characteristics of skin of different developmental stages and hypertrophic scars were detected with pathological methods, gene expression of ERK5 and MEK5 was examined with reverse transcription-polymerase chain reaction analysis (RT-PCR).

RESULTSIn early gestational fetal skin, genes of ERK5 and MEK5 were strongly expressed, while in late gestational skin and children skin, the expression of ERK5 and MEK5 was apparently decreased (P < 0.05). In normal skin, the level of gene expression of ERK5 was lower. In proliferative hypertrophic scars, mRNA content of this gene was apparently increased. In mature scars, the content of this gene transcript was 3.2 times the normal skin. In contrast, the levels of MEK5 transcript in normal skin and hypertrophic scars of various phases showed no substantial changes (P > 0.05).

CONCLUSIONERKS medicating signaling pathway might be involved in regulating cutaneous development at the embryonic stage and determining cutaneous structure ad function. The increase of gene transcription of ERK5 and MEK5 in younger fetal skin might be a reason for rapid proliferation of the skin cells and scraless healing of skin. The activation of ERK5 gene expression in hypertrophic scars versus normal skin might be one of the mechanisms controlling the formation of hypertrophic scars, in which the role of MEK5 needed to be further studied.