Topical Application of Cyclosporin A Induces Rapid Remodeling of Damaged Anagen Hair Follicles in Cyclophosphamide-Administered Mice

In the 2001 study, adult C3H mice with anagen IV or VI hair follicles were treated with cyclophosphamide to induce hair loss, followed by daily applications of cyclosporin A (CSA) or minoxidil (MXD). The study found that 0.5% CSA promoted thick and long hair regrowth in anagen IV follicles after 21 days, while 1% MXD and control treatments resulted in sparse, short hairs. Anagen VI follicles experienced complete alopecia, but both 0.5% CSA and 1% MXD led to hair regrowth after 14 days. Histological analysis showed that anagen IV follicles could remodel after damage, a process enhanced by CSA. The study concluded that hair follicles respond differently to damage based on their growth stage and that CSA can induce rapid remodeling and regrowth in damaged anagen IV follicles. The number of mice in each experimental group ranged from five to six.