The protective effect and mechanism of crude polysaccharide from Broussonetia papyrifera flower on UV-induced skin photodamage
To investigate the protective effect of crude polysaccharide from Broussonetia papyrifera flower on skin photodamage,a total of 56 female Kunming mice were randomly divided into 7 groups:control group,model group,matrix gel group,vitamin A group,and crude polysaccharide low-dose,medium-dose and high-dose groups.The exposed back skin of the mice was irradiated by UVA to induce skin photodamage model,and the drugs were applied to the skin 1 hour before irradiation.After 8 weeks of continuous irradiation,the back skin was scored.The effects of crude polysaccharide from Broussonetia papyrifera flower on the back skin morphology,skin thickness and collagen fibers were investigated by hematoxylin-eosin and Masson staining.And the contents of skin hydroxyproline,SOD,GSH-Px,CAT,MDA,TNF-α,IL-1β,and IL-6,and the protein expressions of MMP-1/3,Nrf2,HO-1 and NF-κB pathway were also examined.Pre-treated skin with different dose of crude polysaccharide gel 1 hour before UVA irradiation can improve roughness and ulceration of the back skin to different degrees,ameliorate skin thickening,and dermal collagen damage.At the same time,the activities of SOD,GSH-Px and CAT in skin tissue are increased,and the content of MDA is decreased(P<0.05).The contents of pro-inflammatory cytokines,TNF-α,IL-1β and IL-6,are decreased(P<0.05).The contents of MMP-1 and MMP-3 are decreased significantly(P<0.05),the expression of Nrf2 and HO-1 protein are increased(P<0.01),and p-p65/p65 protein are decreased significantly(P<0.05)in the mouse back skin by pre-treatment with crude polysaccharide gel.The crude polysaccharide from Broussonetia papyrifera flower has a strong antioxidant activity in vitro,and a protective effect on UVA-induced mice skin photodamage in vivo.The mechanism may be related to the activation of Nrf2 and inhibition of NF-κB signaling pathway,leading to the regulation of antioxidative enzyme SOD and improvement of inflammatory response.
crude polysaccharide of Broussonetia papyrifera flowerskin photodamageoxidative stressproinflammatory cytokineNrf2 pathway
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