Time course of differentiation of different cell types in 3D-reconstructed eccrine sweat glands

Epidermal basal cells invaginate into the dermis to form sweat ducts, which then grow downwards further to form secretory coils during the ontogenesis of eccrine sweat glands, but the time course of differentiation of different cell types in 3D-reconstructed eccrine sweat glands remain unclear. In this study, secretory cell-specific marker K7, clear secretory cell-specific marker CA II, dark secretory cell-specific marker GCDFP-15, myoepithelial cell-specific marker α-SMA, inner duct cell-specific marker S100P and outer duct cell-specific marker S100A2 were detected by immunofluorescence staining. The results showed that S100P and S100A2 were first detected at 2 weeks post implantation, K7 and α-SMA at 3 weeks, and GCDFP-15 and CA II at 4 weeks. The differentiation of ducts preceded secretory coils in 3D-reconstructed eccrine sweat glands. After 8 weeks post implantation, the distribution of these markers in 3D-reconstructed eccrine sweat glands was similar to that in native ones, and the percentage of the 3D-reconstructed glands expressing these markers maintained steady. We conclude that although the 3D-reconstructed and native eccrine sweat glands originated from different cells, the differentiation of different cell types in 3D-reconstructed eccrine sweat glands parallels the sequence observed during embryonic development.