绞股蓝皂苷对光损伤小鼠皮肤中核因子κB、p38MAPK的影响

摘要

目的 观察绞股蓝皂苷(GP)对光损伤Balb/C小鼠皮肤中核转录因子kappa-B(NF-κB)、p38丝裂原活化蛋白激酶(p38MAPK)的影响,进一步探讨GP抗皮肤光损伤的可能机制.方法 将80只雌性Balb/C小鼠随机分为8组,每组10只.①空白对照组:不做任何处理；②UVB模型组:UVB照射60 s；③GP乳膏Ⅰ组；④GP乳膏Ⅱ组；⑤维生素E乳膏Ⅰ组；⑥维生素E乳膏Ⅱ组；⑦基质Ⅰ组；⑧基质Ⅱ组.Ⅰ组均先外涂相应的乳膏或基质,30 min后照射UVB 60 s；Ⅱ组均先用UVB照射60 s,30 min后外涂相应的乳膏或基质.采用隔日UVB照射7次Balb/C小鼠建立皮肤光损伤动物模型,应用Western印迹法检测小鼠皮肤中NF-κB抑制蛋白(IκB蛋白)、κB抑制蛋白激酶(IKK蛋白)及p38MAPK、磷酸化p38MAPK(pp38)的表达.结果 空白对照组小鼠表皮中IκB、IKK蛋白未见表达.UVB模型组小鼠表皮中IκB蛋白水平为0.40±0.07,IKK蛋白为2.01±1.75.GP乳膏Ⅰ组与Ⅱ组IκB蛋白表达(分别为1.63±0.85和0.90±0.40)明显高于UVB模型组(P值均＜0.05),IKK蛋白表达(分别为0.23±0.12和0.45±0.29)明显低于UVB模型组(P值均＜0.05),与维生素E组小鼠皮肤中IκB蛋白、IKK蛋白的表达结果相似.各组p38MAPK表达量没有明显差异.GP乳膏Ⅰ组与Ⅱ组磷酸化p38MAPK表达水平(分别为0.425±0.054和0.571±0.090)明显低于UVB模型组(0.835±0.049),与维生素E组相似.结论 UVB照射能促使NF-κB活化,激活磷酸化p38MAPK; 1.5％GP乳膏能抑制UVB诱导的NF-κB通路及p38MAPK的激活,可能是其抗炎、抗光损伤的作用机理之一.%Objective To observe the effects of gypenosides (GP) on nuclear factor κB (NF-κB) and p38 mitogen activated protein kinase (p38MAPK) signaling pathways in photodamaged skin of mice,and to explore the mechanisms underlying the protective effects of GP against photodamage.Methods Eighty Balb/C female mice were randomly divided into 8 groups: blank control group receiving no treatment,ultraviolet B (UVB) model group receiving UVB irradiation for 60 seconds,GP group Ⅰ receiving topical GP treatment followed by UVB irradiation,GP group Ⅱ receiving UVB irradiation followed by topical GP treatment,VitE group Ⅰ receiving topical VitE treatment followed by UVB irradiation,VitE group Ⅱ receiving UVB irradiation followed by topical VitE treatment,matrix group Ⅰ receiving topical matrix treatment followed by UVB irradiation,matrix group Ⅱ receiving UVB irradiation followed by topical matrix treatment.UVB irradiation lasted 60 seconds at one time,and was given once every other day for 7 times to establish a skin model of photodamage.The interval between irradiation and topical treatment was 30 minutes in all the groups except the control group and UVB model group.After the last treatment,mice were sacrificed.Western blot was performed to measure the protein expressions of inhibitor of NF-κB(IκB),inhibitor of NF-κB kinase (IKK),p38MAPK as well as phosphorylated p38MAPK (pp38) in skin tissue from the mice.Results No expressions of IκB or IKK were observed in the blank control group.The expression level of IκB was 0.40 ± 0.07 in UVB model group,significantly lower than that in GP group Ⅰ (1.63 ± 0.85,P ＜ 0.05) and GP group Ⅱ (0.90 ± 0.40,P ＜ 0.05),whereas the level of IKK protein was higher in UVB model group than in the GP group Ⅰ and Ⅱ (2.01 ± 1.75vs.0.23 ± 0.12 and 0.45 ± 0.29,both P ＜ 0.05).No significant difference was observed in the expression of IκB or IKK proteins between the GP group Ⅰ,Ⅱ,VitE group Ⅰ and Ⅱ or in the expression of p38MAPK between the 8 groups.The phosphorylated p38MAPK expression in UVB model group was significantly higher than that in GP group Ⅰ and Ⅱ (0.835 ± 0.049 vs.0.425 ± 0.054 and 0.571 ± 0.090,both P＜ 0.05),but similar to that in VitE groups.Conclusions UVB can activate NF-κB and phosphorylated p38MAPK signaling pathways; GP 1.5％ cream can inhibit UVB-induced activation of NF-κB and p38MAPK pathways,which may be one of the mechanisms underlying its protective effects against inflammation and photodamage.