Matrix Metalloproteinase-9 Is Involved in the Regulation of Hair Canal Formation

The study demonstrated that Matrix Metalloproteinase-9 (MMP-9) played a crucial role in hair canal formation during hair follicle development. MMP-9 facilitated extracellular matrix remodeling necessary for hair shaft emergence, as observed in embryonic and early postnatal mouse skin. MMP-9 knockout mice (n=7) showed significant delays in hair shaft emergence and reduced hair canal width compared to wild-type mice (n=5), highlighting MMP-9's importance in proper hair follicle morphogenesis. This research provided insights into the molecular mechanisms of hair follicle development and suggested potential therapeutic targets for hair growth disorders, although the exact mechanisms and involvement of other metalloproteinases in human hair follicle development remained unclear.