photoprotective effects of oral pterostilbene in uvb-induced skin photoaging balb/c mouse model

Background: photoaging results from prolonged and repeated exposure to solar ultraviolet-b (uvb) radiation. while sunscreen is effective in preventing ultraviolet (uv)-induced skin damage, oral antioxidants may offer additional protective benefits. pterostilbene (ps), a compound found in blueberries and pterocarpus marsupium heartwood, is recognized for its anti-aging and anti-photocarcinogenic properties. however, its photoprotective effects on photoaging have not been extensively studied. objectives: this study investigates the photoprotective effects of oral ps in a uvb-induced skin photoaging balb/c mouse model. methods: sixteen 7-week-old female balb/c mice were randomly assigned to groups using an online random number generator. the mice received daily oral doses of corn oil or ps at 30 and 60 mg/kg in corn oil. after a 2-week period without uvb exposure, the uvb (-) group remained unexposed, while the uvb (+), uvb (+) ps30, and uvb (+) ps60 groups were subjected to increasing uvb doses three times a week for eight weeks, resulting in a cumulative exposure of 3.7 j/cm2. weekly pinch tests were conducted throughout the 8-week exposure period. photographs of the mice skin were taken before culling, and skin samples were collected for hematoxylin eosin (h e) staining, masson's trichrome staining, reduced glutathione (gsh) assay, and melanin content assay. results: the uvb (+) ps30 group showed reduced erythema and wrinkles, while the ps60 group exhibited the most significant improvement in photoaged skin, with eliminated erythema, reduced wrinkles, and smoother skin. the ps30 (4.05 ± 0.11 seconds) and ps60 (3.65 ± 0.06 seconds) groups significantly reduced pinch test times compared to the uvb (+) group (4.96 ± 0.12 seconds), indicating improved skin elasticity. additionally, ps30 (61.87 ± 3.58 µm) and ps60 (43.64 ± 2.08 µm) significantly reduced epidermal thickness compared to the uvb (+) group (67.39 ± 1.69 µm). collagen content significantly increased in the ps30 (1.41 ± 0.04) and ps60 (1.27 ± 0.02) groups compared to the uvb (+) group (1.11 ± 0.01). the gsh levels (µmol/mg) were significantly higher in the ps30 (0.56 ± 0.01) and ps60 (0.56 ± 0.02) groups compared to the uvb (+) group (0.48 ± 0.01), with no significant difference between the ps doses. melanin content (µmol/mg) in the ps30 (0.34 ± 0.01) and ps60 (0.35 ± 0.01) groups showed no significant difference compared to the uvb (+) group (0.387 ± 0.04). conclusions: oral ps demonstrated significant photoprotective effects in uvb-induced skin photoaging, suggesting its potential as an anti-photoaging agent in the cosmeceutical and nutraceutical industries.