Development, Structure, and Keratin Expression in C57BL/6J Mouse Eccrine Glands

The study described the development and structure of eccrine sweat glands in C57BL/6J mice, which are only present on their footpads and resemble human eccrine glands when mature. The initial formation of these glands was observed at 16.5 days postconception (DPC) in mouse embryos, with further development and cell organization by 6 to 7 postpartum days (PPD). The expression of mouse-specific keratins (K1, K10, K14, K17, K5, and K6) was detailed, noting that K1 and K10 were confined to the upper layers of the skin, while K14 and K17 were in the basal layer and gland anlagen in embryos. K5 followed a similar pattern to K17, and K6 was only seen in the duct's luminal cell layer after birth. By 21 PPD, the gland openings were visible on the footpad surface, which lacked the ridge and crease system found in human fingers. This information provides a reference for skin research using genetically engineered mice.