In Vivo Non-Invasive Observation of Dynamic Changes in Hair Shaft, Melanin, and Collagen During the C57BL/6 Follicle Cycle

This study utilized non-invasive methods to monitor the dynamics of hair shaft, melanin, and collagen in C57BL/6 mice throughout multiple hair follicle cycles. Techniques such as dermoscopy, photography, electron microscopy, and second harmonic generation (SHG) were employed to observe and quantify changes during the anagen, catagen, and telogen phases. The accuracy of these observations was validated using hematoxylin and eosin staining, liquid crystal polarizing imaging, and Sirius Red staining. The research provides a foundation for non-invasive evaluation of hair growth cycles, which could aid in developing treatments for hair loss. The authors reported no competing interests.