Effects of the Higenamine, a Potent Compound from Aconitum, on UVB-Induced Photoaging in Hairless Mice

Early stage ultraviolet irradiation damage to skin collagen can be suppressed by HPA axis control via controlled CYP11B

UV rays constitute an extremely important environmental factor known to operate adaptative mechanisms that maintain biological homeostasis in the skin, adrenal glands, and the brain. The skin is extremely vulnerable to UV rays. UV rays deform collagen, the main component of elastic fibers, decreasing its normal function, and ultimately reducing skin's elasticity. We confirmed that psychological stress occurring during the early stages of UVB-irradiation degraded collagen function by inhibiting production rather than the decomposition of collagen, thereby promoting skin aging. UV irradiation for 0-2 weeks increased the level of a stress factor, corticosterone (CORT). High-performance liquid chromatography and western blot analysis confirmed that the increase was caused by enhanced CYP11B1/2 levels during steroid synthesis in the adrenal gland. Precursor levels decreased significantly during the two weeks of UV irradiation. Skin collagen and collagen fibers reduced drastically during this time. Furthermore, the administration of osilodrostat, a USFDA-approved drug that selectively inhibits CYP11B1/2, preserved skin collagen. The mechanism underlying the reduction of CORT by osilodrostat confirmed that the amount of skin collagen could be preserved with treatment. In addition, upon suppression of the CORT receptor, the amount of collagen was controlled, and skin aging was suppressed by the hypothalamic-pituitary-adrenal axis. Therefore, this study confirmed an inverse relationship between adrenal CYP11B1/2 levels and collagen during the initial stages of UV irradiation of the skin. The findings of this study may be useful for developing new detection mechanisms for aging, following their further verification.