**Author details**

**4.4. Effect of leptin on the migration of human epidermal keratinocytes**

32 Wound Healing - New insights into Ancient Challenges

significantly accelerated the migration of human epidermal keratinocytes.

Moreover, to elucidate the effect of leptin on cell migration around the skin wounded area, scratch assay using human epidermal keratinocytes was performed. The assay was performed using CytoSelect Wound Healing Assay kit (Cell Biolabs Inc., San Diego, USA) according to the manufacturer's instructions. After preparation, the cells were treated with or without 100 ng/mL of leptin. Images of wound healing were captured using a phase-contrast microscope at 0, 3, 6, 9, 12, 18, and 24 h after the preparation. The area of open wound field was calculated by using ImageJ software [32]. Consequently, the significant effect was not observed during initial 12 h. However, the area without cells decreased significantly in leptin-treated group compared with control group from 18 to 24 h (**Figure 7**). This assay revealed that leptin

**Figure 7.** Effect of leptin on the migration of human epidermal keratinocytes. Leptin accelerated the migration of hu-

Leptin is capable of promoting wound healing of skin by influencing epidermal keratinocytes proliferation, differentiation/function and migration, and angiogenesis in the connective tissue beneath the wounded area. Moreover, we showed that single dose and topically administration of leptin could promote wound healing in the skin without any side effects by using an adequate drug delivery system [33]. In addition to these findings, our previous study demonstrated that local administration of leptin could promote wound healing in the oral mucosa by enhancing epithelial cell migration and angiogenesis in the connective tissue beneath the wound [34]. Taken together, leptin is proven to play physiological roles in wounded area not only as a systemic hormone but also as a local growth factor. Importantly, these findings presented in this chapter declared the possible and promising usefulness of leptin as a new

man epidermal keratinocytes, significantly. \*P < 0.05.

wound-healing promoting agent.

**5. Conclusion**

Reiko Tokuyama-Toda and Kazuhito Satomura\*

\*Address all correspondence to: satomura-k@tsurumi-u.ac.jp

Department of Oral Medicine and Stomatology, Second Department of Oral and Maxillofacial Surgery, School of Dental Medicine, Tsurumi University, Yokohama, Kanagawa, Japan
