Photochemoprotective effect of Calluna vulgaris extract on skin exposed to multiple doses of ultraviolet B in SKH-1 hairless mice.

UVB is a major cause of nonmelanoma skin cancer in humans. Photochemoprevention represents an important strategy in protecting the skin against the detrimental effects of ultraviolet B (UVB). We investigated the activity of Calluna vulgaris (Cv) delivered via a hydrogel on 3 main pathways (oxidative stress, inflammation, DNA damage) on skin exposed to multiple doses of UVB in SKH-1 mice. Fifty female mice were divided randomly into 5 groups: control, vehicle, UVB irradiated, Cv + UVB irradiated, and Cv + vehicle + UVB irradiated. The extract was applied topically on the skin in a dose of 4 mg polyphenols/cm2 30 minutes before each UVB (240 mJ/cm2) exposure over 10 consecutive days. Malondialdehyde, reduced glutathione, tumor necrosis factor-α, interleukin-6, cyclobutane pyrimidine dimer (CPD) levels, sunburn cell formation and epidermal thickness, and the number of epidermal cell layers in skin were evaluated 24 hours after the last treatment. UVB increased cytokine levels (P < 0.001), formation of CPDs (P < 0.001) and sunburn cells (P < 0.001), and the epidermal thickness and number of epidermal cell layers (P < 0.001) compared with the control group. The topical application of Cv protected the skin against inflammation and DNA damage, as shown by a decreased number of CPDs (P < 0.001) and sunburn cells (P < 0.001). The administration of Cv via hydrogel may be a viable method for chemoprevention..

The effects of grape seeds polyphenols on SKH-1 mice skin irradiated with multiple doses of UV-B.

The study investigated the protective activity of red grape seeds (Vitis vinifera L, Burgund Mare variety) (BM) extracts in vivo on multiple doses of ultraviolet radiation (UV)-B-induced deleterious effects in SKH-1 mice skin. Eighty 8-weeks-old female SKH-1 mice were divided into 8 groups: control, vehicle, UV-B irradiated, vehicle+UV-B irradiated, BM 2.5mg polyphenols (PF)/cm(2)+UV-B irradiated, BM 4 mg PF/cm(2)+UV-B irradiated, UV-B+BM 2.5mg PF/cm(2), UV-B+BM 4 mg PF/cm(2). The extract was applied topically before or after each UV-B exposure (240 mJ/cm(2)), for 10 days consecutively. The antioxidant activity of BM extract is higher than gallic acid (k(BM)=0.017, k(gallic acid)=0.013). Multiple doses of UV-B generated the formation of cyclobutane pyrimidine dimers (CPDs) and sunburn cells, increased glutathione peroxidase (GPx) and catalase (CAT) activities respectively glutathione (GSH) and IL-1ß levels in skin. In group treated with 2.5mg PF/cm(2) before UV-B irradiation BM extract inhibited UV-B-induced sunburn cells, restored the superoxide dismutase (MnSOD) activity, increased insignificantly CAT and GPx activities and reduced IL-1ß level. The BM 4.0 mg PF/cm(2) treatment decreased GSH level and reduced the percentage of CPDs positive cells in skin. Both doses of BM extract administered after UV-B irradiation increased the MnSOD and GPx activities and reduced the formation of sunburn cells in skin. Our results suggest that BM extract might be a potential chemo-preventive candidate in reducing the oxidative stress and apoptosis induced by multiple doses of UV-B in skin.