Ovariectomy accelerates photoaging of rat skin

We have previously reported the formation of wrinkles, a decrease in skin e lasticity and a loss in the linearity of dermal elastic fibers in rat hind limb skin irradiated with ultraviolet radiation in wavelength ranging 290-3 20 nm (UVB) at a suberythemal dose for 6 weeks, Estrogens are considered ef fective in preventing photoaging in postmenopausal females, but the role of estrogen in the skin remains unclear. In this study we have evaluated the influence of short-term chronic UVB irradiation at a suberythemal dose on t he skin of ovariectomized rats. An ovariectomy or a sham operation was perf ormed on each 3 week-old female Sprague-Dawley rat, Starting 1 week after t he operation the hind limb skin of each rat was irradiated with UVB at a su berythemal dose (130 mJ/cm(2)) three times a week for 3 or 6 weeks. Decreas es in elasticity and wrinkle formation in the skins of ovariectomized anima ls were induced more quickly than in the skins of sham-operated animals fol lowing UVB irradiation. The linearity of elastic fibers in the ovariectomy group decreased significantly compared with the sham-operation group, but e rythema in the ovariectomy group was induced more readily than in the sham- operation group following UVB irradiation. These findings suggest that decr eases in the estrogen levels after ovariectomy accelerate photoaging in ter ms of the morphology and physical properties of the skin surface and the th ree-dimensional structure of elastic fibers.