DHA通过抑制脊髓背角TLR4/NF-κB通路缓解特应性皮炎模型小鼠瘙痒

DHA alleviates atopic dermatitis pruritus by inhibiting the activation of TLR4/NF-κB signal pathway in the spinal cord of mice

目的:研究二十二碳六烯酸(DHA)对2,4二硝基氟苯(DNFB)特应性皮炎模型小鼠脊髓Toll样受体4型(TLR4)及其下游分子核因子κB(NF-κB)活化的调节作用。方法:将雄性C57BL/6J小鼠分为对照组(control)、DHA处理组(DHA)、特应性皮炎模型组(DNFB)和DHA治疗特应性皮炎组(DNFB+DHA)。利用腹部涂抹DNFB的方法制备特应性皮炎小鼠模型,通过灌胃方法给予小鼠DHA治疗,使用小鼠行为学视频采集系统评估小鼠搔抓行为,使用ELISA试剂盒检测小鼠脑脊液中TNF-α、IL-6、IL-4、IL-1β、IL-12和IgE含量变化,使用Western Blot检测小鼠脊髓背角中TLR4及其下游分子NF-κB(p65)蛋白含量变化。结果:连续14 d灌胃600 mg/kg·d DHA能够逆转DNFB模型小鼠搔抓行为的增加;逆转脊髓中促进炎症和瘙痒的因子TNF-α、IL-6、IL-4、IL-1β和IL-12的表达增加,但是对IgE并无影响;逆转脊髓背角TLR4及其下游分子NF-κB(p65)蛋白表达。结论:DHA可以通过抑制脊髓背角TLR4介导的NF-κB活化进而抑制DNFB诱导的特应性皮炎模型小鼠的瘙痒行为。

Objective:To study the effect of docosahexaenoic acid(DHA,22:6 n-3)on 2,4-dinitrofluorobenzene(DNFB)atopic dermatitis model mouse spinal cord toll-like receptor 4(TLR4)and its downstream molecules in the regulation of nuclear factor kappa-B(NF-κB)activation.Methods:Male C57 BL/6 J mice were divided into control group(control),DHA-treated group(DHA),atopic dermatitis model group(DNFB),and DHA-treated atopic dermatitis group(DNFB+DHA).Mouse model of atopic dermatitis was prepared by smearing DNFB on the abdomen,and the mice were treated with DHA by gavage.The mouse behavior video acquisition system was used to evaluate the scratching behavior of the mice.ELISA kits were used to detect TNF-α,IL-6,IL-4,IL-1β,IL-12,IgE,and other cytokines involved in atopic dermatitis pruritus in the cerebrospinal fluid of the mice.Western Blot was used to detect TLR4 and its downstream molecule NF-κB(p65)protein in the dorsal horn of mouse spinal cord content changes.Results:Continuous 14-day gavage of 600 mg/kg·d DHA can rescue the increase in scratching behavior in DNFB model mice;rescue the factors TNF-α,IL-6,IL-4,IL-1β,and IL-12 in the spinal cord that promote inflammation and pruritus.The expression of TNF-α,IL-6,IL-4,IL-1β,and IL-12 increased,but had no effect on IgE;reversed the increased protein expression of TLR4 and its downstream molecules NF-κB(p65)in the dorsal horn of the spinal cord.Conclusion:DHA could inhibit the pruritus behavior in DNFB chronic itch model mice by inhibiting TLR4-mediated NF-κB activation.