Leptin promotes wound healing in the oral mucosa.

Hirochika Umeki,Susumu Tadokoro,Mitsuki Tezuka,Mitsuru Okubo,Kazuhito Satomura,Seiko Tatehara,Reiko Tokuyama,Shinji Ide,Dimitris Kletsas

doi:10.1371/journal.pone.0101984

Abstract

IntroductionLeptin, a 16 kDa circulating anti-obesity hormone, exhibits many physiological properties. Recently, leptin was isolated from saliva; however, its function in the oral cavity is still unclear. In this study, we investigated the physiological role of leptin in the oral cavity by focusing on its effect on wound healing in the oral mucosa.MethodsImmunohistochemical analysis was used to examine the expression of the leptin receptor (Ob-R) in human/rabbit oral mucosa. To investigate the effect of leptin on wound healing in the oral mucosa, chemical wounds were created in rabbit oral mucosa, and leptin was topically administered to the wound. The process of wound repair was histologically observed and quantitatively analyzed by measuring the area of ulceration and the duration required for complete healing. The effect of leptin on the proliferation, differentiation and migration of human oral mucosal epithelial cells (RT7 cells) was investigated using crystal violet staining, reverse transcription polymerase chain reaction (RT-PCR) and a wound healing assay, respectively.ResultsOb-R was expressed in spinous/granular cells in the epithelial tissue and vascular endothelial cells in the subepithelial connective tissue of the oral mucosa. Topical administration of leptin significantly promoted wound healing and shortened the duration required for complete healing. Histological analysis of gingival tissue beneath the ulceration showed a denser distribution of blood vessels in the leptin-treated group. Although the proliferation and differentiation of RT7 cells were not affected by leptin, the migration of these cells was accelerated in the presence of leptin.ConclusionTopically administered leptin was shown to promote wound healing in the oral mucosa by accelerating epithelial cell migration and enhancing angiogenesis around the wounded area. These results strongly suggest that topical administration of leptin may be useful as a treatment to promote wound healing in the oral mucosa.

Highlights

Leptin, a 16 kDa circulating anti-obesity hormone, exhibits many physiological properties
The expression pattern of Ob-R in oral mucosa was common between human and rabbit
Histological observation showed that the wound area decreased much faster in the leptin-treated group compared with the control group (Fig. 2B and 2C)

Summary

Introduction

A 16 kDa circulating anti-obesity hormone, exhibits many physiological properties. Leptin was isolated from saliva; its function in the oral cavity is still unclear. We investigated the physiological role of leptin in the oral cavity by focusing on its effect on wound healing in the oral mucosa. The surface of the oral cavity is covered by oral mucosa, a moist lining that communicates with the external environment. Functions of the oral mucosa include protection, sensation and secretion [1]. The oral mucosa protects deeper tissues and organs in the oral region by separating them from the external environment. Numerous minor salivary glands are associated with the oral mucosa, and the saliva secreted by these glands contributes moistening, lubrication [3] and topophylaxis within the oral cavity

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Results

Conclusion