Novel Protective Effect of Prostaglandin for Timely Hair Follicle Regeneration from Radiation Injury

This study investigated the effect of prostaglandin on hair follicle regeneration following radiation injury. The researchers found that local prostaglandin E2 (PGE₂) pretreatment reduced hair loss from radiation injury by preventing entry into catagen and telogen. Quiescent hair follicle bulge stem cells were not activated, but the dystrophy of hair bulbs where hair follicle transit amplifying cells (TACs) reside was reduced and concentric layers of anagen hair follicle structures were quickly regenerated. PGE₂ pretreatment halted the proliferation of TACs and reduced the radiosensitivity of TACs through cell cycle modulation. The study suggests that PGE₂ pretreatment might protect hair follicle TACs against radiation injury through modulating their cell cycles and the preserved TACs can serve as 'reserve stem cells" to regenerate the lost structures to resume anagen growth, thus bypassing the long downtime needed to rest hair cycles through telogen for bulge stem cell activation.