Effects of Immune Responses Mediated by Topological Structures of Three-Dimensional Bioprinted Scaffolds on Hair Follicle Cycle in Mice

The study investigated the effects of immune responses mediated by different topological structures of 3D bioprinted scaffolds on hair follicle cycles in mice. Nine female C57BL/6J mice were divided into three groups, each receiving a different scaffold (T45, T60, T90) based on the rotation angles of the printhead. Results showed that on post-implantation day 7, hair growth was more pronounced in the T45 and T90 groups compared to the T60 group, where hair growth was slower. The T60 group exhibited a significantly thicker fiber capsule and higher expression levels of CD68 and BMP-2 proteins, indicating a stronger immune response, while TNF protein levels were lower compared to the other groups. The study concluded that moderate immune responses promote hair growth, whereas excessive responses inhibit the hair follicle's entry into the anagen phase.