2,4-二硝基氯苯诱导BN大鼠慢性特应性皮炎模型的建立和验证

Establishment and evaluation of a chronic atopic dermatitis model induced by 2,4-dinitrochlorobenzene in Brown Norway rats

目的建立2,4-二硝基氯苯诱发的Brown Norway(BN)大鼠特应性皮炎(atopic dermatitis,AD)模型,并评估验证其在药效试验中的应用。方法BN大鼠随机分为对照组、模型组、他克莫司组。分别于1、3、7、9、12、14、16、19、21、23和25 d对模型组和他克莫司组BN大鼠双耳涂布0.5%2,4-二硝基氯苯(DNCB)溶液,每耳40μL。对照组在相同时间给予等容积的基质溶液。他克莫司组在造模期间给予他克莫司软膏涂抹右耳,连续25 d。试验期间对耳部皮肤进行炎症评分和耳厚度测定;造模26 d后取耳片进行称重;部分耳片组织行苏木素-伊红染色和甲基胺蓝染色,剩余耳片匀浆测定IgE含量。结果模型组自造模9 d起耳厚度明显增加,12 d出现明显的耳组织炎症症状,16~25 d处于高峰阶段;造模26 d,模型组耳重量明显增加,IgE含量明显升高,耳组织呈表皮增厚、表皮内和真皮层炎细胞浸润、肥大细胞浸润等病理改变。他克莫司软膏明显改善上述指标。结论DNCB诱导BN大鼠发展出稳定的AD样症状,适用于药物药效作用评价。

Objective To establish and evaluate a chronic model of atopic dermatitis(AD)induced by 2,4-dinitrochlorobenzene(DNCB)in Brown Norway rats.Methods Brown Norway rats were randomly divided into negative,model,and tacrolimus groups.The ear skin of rats in model and tacrolimus groups were challenged by 0.5%DNCB at days 1,3,7,9,12,14,16,19,21,23 and 25.Rats in the control group were administered a substrate solution at the same volume at the same time points.Rats in the tacrolimus group were transdermally administered tacrolimus ointment for 25 consecutive days.The inflammation score of ear skin and the thickness of ear tissue were evaluated.Ear tissues were collected and weighted after 26 days of modeling.Histopathological examination and toluidine blue staining of ear tissue were also performed.The IgE level in ear tissue was detected.Results The ear thickness in model rats was significantly increased after 9 days of challenge by DNCB,while whereas inflammation score was remarkedly improved after 12 days and reached a peak at 16~25 days.The weight of ear tissue and the IgE level in the ear were increased at day 26 of challenge.Pathological changes,such as epidermal thickening,inflammatory cell infiltration,and mast cell infiltration,occurred in the model group.Tacrolimus significantly reversed these changes.Conclusions Brown Norway rats challenged by DNCB develop stable AD-like symptoms,which are appropriate for pharmacological evaluation.