Cytokeratin Expression at Different Stages in Sweat Gland Development of C57BL/6J Mice

Sweat glands exhibit a documented role in epidermal reepithelialization after wounding. However, the regenerative potential of sweat glands has remained underappreciated due to the absence of useful markers for the analysis of determination and differentiation processes in the developing eccrine sweat gland from epithelium. Although the current knowledge of keratin expression in most of the different origins has been described, it remains widely shared and not unified in eccrine sweat glands of C57BL/6J mice that are commonly used as animal models for sweat gland and wound healing studies, both at the molecular and cellular levels. Aiming to answer this question, we have investigated the changes in cytokeratin expression patterns during the embryonic, neonatal, juvenile, and young adult stages (E12.5, E17.5, P0.5, P5, and P28). In this article, we demonstrate that the morphology of murine sweat gland progenitor cells are similar to epidermal stem cells before birth (E12.5 and E17.5); at postnatal stages, the duct formed gradually and curled to glob. K8 and K19 were expressed in the eccrine sweat gland cells at all times and highly expressed after birth at both gene and protein levels. Also, histological results revealed K8 and K19 positive cells localized in the secretary portion of glands. Meanwhile, K14 strongly expressed both in vivo and in vitro at E12.5, while it weakly expressed at other stages. Moreover, K10 was rarely detected before birth, but it expressed positively in vivo and in vitro only at the protein level after birth. These data indicate the pattern of main cytokeratin expression at different stages during murine sweat gland development and might provide an efficient tool for sweat gland research and exciting potential for developing targeted therapies for wound healing.