Effects of leptin on growth factor expression in human keratinocytes.

Wound healing involves the coordinated activity of epithelial, endothelial, mesenchymal, and inflammatory cells. Leptin, an adipocyte hormone, regulates energy homeostasis and metabolism. The objective of this work was to explore how different concentrations and exposure durations of leptin influence keratinocytes under controlled in vitro conditions. For this purpose, in vitro wound closure was assessed under leptin exposure, and the expression of TGF-α, TGF-β1, KGF, FGFR2, and the proliferation marker Ki67 was evaluated. There were control, 100 ng/mL, 200 ng/mL, 400 ng/mL, and 800 ng/mL leptin-treated groups in the study. Cell viability was assessed using the WST-1 test, and TGF-α, TGF-β1, KGF, FGFR2, and Ki67 expression was evaluated by immunocytochemistry. Wound areas were measured at 24 and 48 h after leptin treatment using ImageJ software. The in vitro wound closure analysis demonstrated the highest wound closure rate (48.5%) in keratinocytes treated with 800 ng/mL leptin for 48 h. Similarly, cell proliferation reached its highest level (136.22% compared with control) following treatment with 800 ng/mL leptin for 48 h. H-score analysis indicated that protein expression increased in a dose- and time-dependent manner in response to leptin treatment. These findings indicate a dose- and time-dependent association between leptin exposure and keratinocyte proliferation, growth factor-related protein expression, and wound closure in vitro. Overall, the results suggest that leptin may be associated with enhanced keratinocyte activation and growth factor-related protein expression under in vitro conditions, which may contribute to increased wound closure in a scratch assay model. However, given the exploratory nature of the study, the findings should be interpreted as associative rather than mechanistic.