DNCB对BALB/c小鼠特应性皮炎的诱导作用及其机制

Induction effect of DNCB on atopic dermatitis BALB/c mice and its mechanism

目的:采用2,4-二硝基氯苯(DNCB)致敏BALB/c小鼠诱导小鼠发生特应性皮炎(AD),阐明DNCB作为半抗原诱导AD的可能致病机制。方法:12只BALB/c小鼠随机分为对照组和AD模型组,每组6只。于实验第1、4、7天,采用1.0%DNCB溶液涂抹于AD模型组小鼠背部皮肤进行致敏,于实验第14、17、19、22、24、27和29天,采用0.5%DNCB溶液涂抹于AD模型组小鼠左耳背部皮肤进行激发。对照组小鼠于相同时间点外用等体积基质溶液。评价2组小鼠皮肤组织炎症评分,观察2组小鼠耳部皮肤外观变化,HE染色和甲苯胺蓝染色观察2组小鼠左耳皮损部位皮肤组织病理形态表现,测量皮损处皮肤组织上皮层厚度,计数皮损处皮肤组织中肥大细胞数,免疫组织化学染色法检测2组小鼠皮损处皮肤组织中白细胞介素4(IL-4)表达水平;ELISA法检测2组小鼠血清IgE水平。结果:AD模型组小鼠皮肤组织炎症评分明显高于对照组(P<0.01),小鼠左耳部皮肤明显红肿、变硬,伴随出现异常的搔抓行为;AD模型组小鼠皮损处皮肤组织上皮层厚度、浸润肥大细胞数、皮损处皮肤组织中IL-4表达水平和血清IgE水平均明显高于对照组(P<0.05或P<0.01)。结论:外用1.0%DNCB致敏和外用0.5%DNCB激发BALB/c小鼠能够成功诱导AD,其机制可能与二者引起皮肤组织中IL-4表达水平和血清IgE水平升高有关。

Objective:To induce the atopic dermatitis(AD)by 2,4-dinitrobenzene(DNCB)in the BALB/c mice,and to explore the possible mechanism of DNCB as hapten to induce AD.Methods:A total of 12 BALB/c mice were randomly divided into control group(n=6)and AD model group(n=6).The dorsal skin of the mice in AD model group was sensitized by 1.0%DNCB at days 1,4,and 7 and the back skin of the left ears were challenged by 0.5%DNCB at days 14,17,19,22,24,27,and 29.The mice in control group were given substrate solution with the same volume at the same time points.The inflammation scores of the skin tissue of the mice in two groups were evaluated,the appearance changes of the ear skin of the mice in two groups were observed,the pathomorphology of the skin tissue in left ear of the mice in two groups were observed by HE staining and toluidine blue staining,the epidermal thickness of the skin tissue at lesion site of the mice in two groups was measured,and the number of mast cells in the skin tissue at lesion site of the mice in two groups was counted;the expression levels of interleukin-4(IL-4)in the skin tissue at lesion site of the mice in two groups was detected by immunohistochemistry staining,and the levels of serum IgE was detected by ELISA method.Results:The inflammation score of the mice in AD model group was higher that in control group(P<0.01).The skin tissue in left ear of the mice in AD model presented as redness swelling and hardening accompaning with abnormal scratching marks;the epidermal thickness,the number of mast cells,the expression level of IL-4 in skin tissue at lesion site and the level of serum IgE of the mice in AD model group were all increased compared with control group(P<0.05 or P<0.01).Conclusion:The AD mouse can be successfully induced by 1.0%DNCB for sensitizing and 0.5%DNCB for challenging in the BALB/c mice,and its mechanism may be related with the increasing of IL-4 expression level in skin tissue and IgE level in serum.