Intervention And Mechanism Of Ginkgo Biloba Extract On Skin Photodamage And Psoriasis

Although ultraviolet(UV)is one of the most common environmental pollution factors,people often ignore the damage caused by UV and go outdoors without enough protection.Chronic and excessive dose of UV lead to sunburn,photodamage and skin cancer.In addition,UV is one of the environmental causes of psoriasis and overdose of UV exacerbates the symptoms of psoriasis.Psoriasis,an inflammation-mediated skin disease,subject patients to great mental stress by causing skin problems and complications such as insomnia,arthritis,and hypertension.With the development of modern medicine and biotechnology,Ginkgo biloba leaves,as a traditional Chinese medicine,is found to be effectively inhibit inflammation and oxidation.According to its bioactivities,Ginkgo biloba leaves has a potential to repair the photodamage and alleviate psoriasis.Therefore,photodamage model on cell and mice,and Imiquimod(IMQ)-treated animal model were used to explore the repairing effect of Ginkgo biloba extract(GBE)on photodamage and inhibitory effect of GBE on psoriasis in this paper.The repairing effect of GBE on UVB-induced photodamage was studied.Reactive oxygen species is a main reason for photodamage.The antioxidant effect of GBE was evaluated by vitro antioxidant experiments.The result showed that GBE scavenged 50%of free radical at 0.12 mg/mL in 1,1-diphenyl-2-picrylhydrazyl(DPPH)test while 0.15 mg/mL in 2,2’-azino-bis(ABTS)test.Thus,GBE exhibited strong antioxidant property.In this paper,Hacat and NIH-3T3 were used to estimate the cell viability with the treatment of different concentration of GBE(50–250μg/mL)after UVB irradiation.It was found that GBE increased cell viability after UVB irradiation.Kunming mice were chosen to establish an animal model to study the skin damage caused by UVB irradiation.Dorsal skin of mice was observed and it was further studied by HE staining and MASSON staining.GBE decreased the abnormal thickness of epidermis caused by UVB and promoted the production of collagen.According to the result of immunohistochemical staining and RT-qPCR,GBE inhibited the expression of proinflammatory cytokines(IL-1,IL-6,TNF-α)and upregulated the expression level of collagen I and collagen III.And GBE may attenuate photodamage by inhibiting NF-κB pathway,which showed in western blotting experiment.Alleviation effect of GBE on psoriasis was also studied.Due to the inhibition of GBE on inflammatory pathway caused by UVB irradiation,GBE attracted great interest in researching the inhibitory effect of psoriasis.GBE and the positive drug Tacrolimus were effectively inhibited scale,erythema and thickness in IMQ-treated balb/c mice.Moreover,GBE and Tacrolimus decreased Transepidermal water loss(TEWL).GBE reduced the thickness of epidermis and the expression of CD8~+T cell,COX-2 in epidermis at the concentration of 50 mg/mL.The mechanism of GBE was further studied by enzyme-linked immunosorbent assay and real-time fluorescent quantitative PCR.Result showed that GBE inhibited the expression of proinflammatory cytokines(IL-1β,IL-6,IFN-γ)and expression level of psoriasis-related cytokines(IFN-α/β,IL-17)at the concentration of 50 mg/mL.Probably,alleviation effect of GBE on psoriasis was attributed to the inhibition of IFN-α/βtranscription and CD8~+T cell growth,which inhibited the expression of some inflammatory cytokines on psoriasis.