基于IL-17/Notch轴土茯苓总黄酮对银屑病小鼠皮肤瘙痒缓解及炎症反应抑制的作用机制研究

Study of total flavonoids from poriacocos on relieving skin pruritus and inhibiting inflammation of psoriasis mice based on IL-17/Notch

关键词:  银屑病  皮肤瘙痒  炎症  土茯苓总黄酮  IL-17/Notch信号轴

Key words:  psoriasis  itchy skin  inflammation  total flavonoids of poriacocos  IL-17/Notch signal axis

摘要:

目的 探讨土茯苓总黄酮对银屑病小鼠皮肤瘙痒及炎症反应的影响，及对白细胞介素（IL）-17/Notch信号轴的调控作用。方法 将50只小鼠按照随机数字表法随机分为正常组、模型组、土茯苓总黄酮低剂量组（简称低剂量组）、土茯苓总黄酮高剂量组（简称高剂量组）和甲氨蝶呤组，每组10只，除正常组外，其余组小鼠背部脱毛，每日涂抹5%咪喹莫特软膏62.5 mg，1次/日，连续7 d，正常组小鼠背部涂抹等量凡士林软膏，低、高剂量组小鼠每日分别用300和500 mg/kg土茯苓总黄酮灌胃，甲氨蝶呤组小鼠每日1 mg/kg甲氨蝶呤片水溶液灌胃，1次/日，连续7 d。评估小鼠皮肤瘙痒次数，进行皮损严重程度指数（PASI）评分，酶联免疫吸附实验（ELISA）检测血清干扰素γ（IFN-γ）、IL-23和肿瘤坏死因子α（TNF-α）含量，苏木精-伊红（HE）染色观察皮肤组织病理损伤，聚合酶链反应（PCR）检测水通道蛋白-3（AQP3）和神经酰胺（Cer）mRNA相对表达量，蛋白印迹法检测IL-17、Notch、Jagged1和Hes-1蛋白相对表达量。结果 正常组小鼠表皮层菲薄，仅有少量炎性细胞；模型组小鼠表皮增厚，伴有角化过度或角化不全，真皮乳头出现水肿，伴血管扩张，棘层增厚，可见大量炎性细胞浸润；低、高剂量组和甲氨蝶呤组小鼠病理损伤不同程度减轻。与正常组比较，模型组小鼠皮肤瘙痒次数、PASI评分、IFN-γ、IL-23和TNF-α含量、IL-17、Notch、Jagged1和Hes-1蛋白相对表达量升高，AQP3和Cer mRNA相对表达量降低（P＜0.05）；与模型组比较，低、高剂量组和甲氨蝶呤组小鼠皮肤瘙痒次数、PASI评分、IFN-γ、IL-23和TNF-α含量、IL-17、Notch、Jagged1和Hes-1蛋白相对表达量降低，AQP3和Cer mRNA相对表达量升高（P＜0.05）；与低剂量组比较，高剂量组和甲氨蝶呤组小鼠皮肤瘙痒次数、PASI评分、IFN-γ、IL-23和TNF-α含量、IL-17、Notch、Jagged1和Hes-1蛋白相对表达量降低，AQP3和Cer mRNA相对表达量升高（P＜0.05）；与高剂量组比较，甲氨蝶呤组小鼠皮肤瘙痒次数、PASI评分、IFN-γ、IL-23和TNF-α含量、IL-17、Notch、Jagged1和Hes-1蛋白相对表达量降低，AQP3和Cer mRNA相对表达量升高（P＜0.05）。结论 土茯苓总黄酮可改善银屑病小鼠皮肤损伤，减轻皮肤瘙痒，抑制对炎症反应，其可能是通过抑制IL-17/Notch信号轴发挥调控作用。

Abstract:

Objective To investigate the effect of total flavonoids of poriacocos on skin pruritus and inflammation in psoriatic mice, and the regulation of interleukin-17 (IL-17) /Notch signaling axis.Methods The 50 mice were divided into normal group, model group, low-dose group, high-dose group and methotrexate group according to random number table method, with 10 mice in each group. Except the normal group, mice in other groups were depilated on their back and smeared with 5% imiquimod ointment 62.5 mg once a day for consecutive 7 days. Mice in normal group were treated with equal amount of vaseline ointment on their back, mice in low-dose and high-dose groups were treated with 300 and 500 mg/kg total flavonoids of poriacocos, respectively, mice in methotrexate group were treated with 1 mg/kg methotrexate tablet aqueous solution, once a day, for consecutive 7 days. The itching times was evaluated, and PASI score was performed. Serum IFN-γ, IL-23 and tumor necrosis factor-α(TNF-α) levels were detected by ELISA. The pathological lesions of skin tissues were observed by HE staining.Results The epidermis of normal group was thin and only a few inflammatory cells were found. In model group, epidermis thickened, accompanied by hyperkeratosis or parakeratosis, dermal papilla edema, vascular dilation, spinous layer thickened, and a large number of inflammatory cell infiltration can be seen. The pathological damage of mice in low-dose, high-dose and methotrexate groups was reduced to different degrees. Compared with normal group, skin itching times, PASI score, the contents of IFN-γ, IL-23 and TNF-α, the relative expression levels of IL-17, Notch, Jagged1 and HES-1 protein were increased in model group, while the relative expression levels of AQP3 and Cer mRNA were decreased(P < 0.05). Compared with model group, skin itching times, PASI score, contents of IFN-γ, IL-23 and TNF-α, relative expression levels of IL-17, Notch, Jagged1 and Hes-1 were decreased in low-dose, high-dose and methotrexate groups, while relative expression levels of AQP3 and Cer mRNA were increased(P < 0.05). Compared with the low-dose group, the itching times, PASI score, the contents of IFN-γ, IL-23 and TNF-α, the relative expression levels of IL-17, Notch, Jagged1 and Hes-1 were decreased in high-dose group and methotrexate group, while the relative expression levels of AQP3 and Cer mRNA were increased(P < 0.05). Compared with the high-dose group, the itching times, PASI score, the contents of IFN-γ, IL-23 and TNF-α, the relative expression levels of IL-17, Notch, Jagged1 and Hes-1 were decreased in methotrexate group, while the relative expression levels of AQP3 and Cer mRNA were increased (P < 0.05).Conclusion Total flavonoids of poriacocos can improve the skin injury of psoriatic mice, reduce skin pruritus and inhibit the inflammatory response, which may play a regulatory role by inhibiting IL-17/Notch signaling axis.