异黄酮预防紫外线照射所致小鼠皮肤损伤

Isoflavone preventing ultraviolet radiation induced skin injuries of mice

目的探讨经皮外用异黄酮霜剂对紫外线照射所致皮肤损伤的作用及机制。方法雄性ICR小鼠随机分成4组(每组12只):对照组小鼠裸露皮肤仅接受纯基质涂布;紫外光照(UV)组、2%异黄酮组和3%异黄酮组小鼠裸露皮肤分别涂布纯基质、含2%或3%异黄酮的药物预处理15 min后,再先后接受长波紫外线(UVA,1.55J/cm2,18min)和中波紫外线(UVB,0.95J/cm2,11min)照射,制作紫外照射损伤的皮肤模型;连续7d后,取被照射部位皮肤组织行H-E染色,观察小鼠皮肤形态学和组织学变化情况,并测定小鼠皮肤组织中炎症因子白介素(IL)-1β、IL-6和肿瘤坏死因子α(TNF-α)的含量以及脂质过氧化产物丙二醛(MDA)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)的含量。结果 (1)UV组小鼠皮肤呈现红斑、结痂等改变,真皮层可见炎症细胞浸润,弹性纤维断裂;经2%或3%异黄酮预处理后,小鼠皮肤色泽均匀,镜下角质层无明显增厚,真皮层内胶原纤维排列较为整齐,无明显炎症细胞浸润。(2)与对照组小鼠相比,UV组小鼠皮肤组织中炎症因子IL-1β、IL-6和TNF-α的含量均增加(P<0.05);给予异黄酮预处理能够减弱紫外线照射所致小鼠皮肤组织中IL-1β、IL-6和TNF-α含量的改变(P<0.05,P<0.01)。(3)与对照组相比,UV组小鼠被照射皮肤组织中MDA含量增加(P<0.05),SOD和CAT含量均降低(P<0.05);给予对照异黄酮预处理能够减弱紫外线照射所致小鼠皮肤组织中MDA、SOD和CAT含量的改变(P<0.05,P<0.01)。结论异黄酮能够通过减轻小鼠皮肤组织脂质过氧化反应、氧化应激和炎症反应预防紫外线照射所致皮肤光老化损伤。

Objective To explore the protective effect of external use of isoflavone cream on ultraviolet radiation induced skin injuries of mice and its mechanisms.Methods A total of 48 male ICR mice were randomly assigned to vehicle（control）,ultraviolet radiation（UV）,2% isoflavone＋UV and 3% isoflavone＋UV groups,with 12 mice in each group,and the naked skin of mice in the four groups were treated with sesame oil（15min）,sesame oil（15min）in combined UV（first radiation with 1.55J/cm^2 long-wave ultraviolet[UVA]for 18 min,and then with 0.95J/cm^2middle-wave ultraviolet[UVB]for 11min）,2%isoflavone（15 min）in combined UV and 3% isoflavone（15 min）in combined UV,respectively. After radiation for 7 days,the UV-exposed skins were obtained to observe the morphological and histological changes using H-E staining.The contents of interleukin（IL）-1β,IL-6,tumor necrosis factorα（TNF-α）,malondialdehyde（MDA）,superoxide dismutase（SOD）and catalase（CAT）in the skins were determined using ELISA or corresponding kits.Results（1）UV irradiation caused erythema and crusting in skin,and inflammatory cell infiltration in the dermis and fractured elastic fiber were observed microscopically.Isoflavone pretreatment effectively ameliorated these damages in mice skin.（2）Compared with the control group,contents of IL-1β,IL-6and TNF-αin the UV group were significantly increased（P〈0.05）;however,the contents of IL-1β,IL-6and TNF-αwere significantly reversed by isoflavone pretreatment（P〈0.05,P〈0.01）.（3）Compared with the control group,the skin MDA content in the UV group was significantly increased（P〈0.05）,SOD and CAT contents were significantly decreased（P〈0.05）;however,the isoflavone pretreatment significantly reversed the alterations of MDA,SOD and CAT（P〈0.05,P〈0.01）.Conclusion Isoflavone exerts protective effects against the ultraviolet induced skin damage in mice through alleviating lipid peroxidation,oxidative stress and inflammatory response.