Expression of connexin43 (Cx43) in the human hair follicle: emphasis on the Cx43 protein levels in the bulge and through the keratinization process

Introduction

Gap junctions form communication compartments between cells. These channels assemble from connexin (Cx) subunits.

Objective

To investigate the immunoexpression of Cx43 in adult human hair follicles.

Materials and methods

Cases were retrospectively obtained from our archives.

Results

We identified immunoexpression of Cx43 in the matrix, the papilla, the outer root sheath, the bulge, the medulla, the cortex, the shaft, and the secretory part of the sebaceous gland. There was very low expression (VLE) of Cx43 in the perifollicular sheath, the mantle, and the arrector pili muscle. The internal root sheath showed high-density expression in the bulb. Such expression abruptly decreased at different points in each of its layers at the point of keratinization. The isthmus showed Cx43 positive staining in the middle layers and all along, whereas there was VLE in the two outermost layers. The infundibulum showed expression all along the middle layers, whereas it showed VLE in the two outermost layers and in the two or three innermost layers.

Conclusions

The bulge contains Cx43. Our results suggest that keratinization in the hair follicle is closely related to the decrease in Cx43 expression.