Mild hyperbaric oxygen activates the proliferation of epidermal basal cells in aged mice

: The proliferation of epidermal basal cells decreases with age. This study examined the effects of exposure to mild hyperbaric oxygen on the proliferative activity of epidermal basal cells in aged mouse skin. Hairless mice aged 5, 34 and 55 weeks were exposed to mild hyperbaric oxygen at 1266 hPa with 36% oxygen for 6 h/day for 1 or 2 weeks. Skin samples were then collected from the back area to evaluate epidermal thickness and the number and proliferative activity of epidermal basal cells. Exposure to mild hyperbaric oxygen had no effect on the epidermal thickness, irrespective of age, but accelerated the proliferative activity of epidermal basal cells in aged mouse skin.