Expression of claudin-1 in the fetal skin during the developmental stage

Abstract

Background: Claudins are integral membrane proteins at tight junctions of simple epithelium and have an important role in cell-cell adhesion and barrier function. Their altered expression modifies the biological function and behavior of epithelial cells. Objective: The purpose of this study was to observe the distribution and the degree of expression of claudin-1 during fetal skin development. Methods: The expression of claudin-1 in the fetal skin was analyzed after immunohistochemical stain was performed on paraffin embedded tissue of sole and scalp of 34 human fetuses, ranging from 10 to 39 weeks of gestational age, using anti-human monoclonal antibody against the claudin-1. Results: Claudin-1 appeared strongly in the sole skin at the 12th week of gestation thereafter expressed more in middle layer in epidermis of the sole and the scalp. Inner root sheaths and early hair germ cells were strongly positive in fetal hair development. Eccrine gland epithelium was positive in later stages. Focal positive expression in superficial layer and strong in middle layer were noted in oral mucosa side of the lip. Conclusion: Claudin-1 showed slightly different expression in skin and oral mucosa and has a important role in the development of tight junction and barrier formation in skin and mucosa during fetal stage.