芒柄花素抑制小鼠Th2型变应性接触性皮炎的机制分析

Formononetin Inhibits Th2 Type Allergic Contact Dermatitis in Mice

目的:研究芒柄花素对过敏性炎症的影响及初步作用机制。方法:采用异硫氰酸荧光素(FITC)诱导Th2型变应性接触性皮炎(allergic contact dermatitis,ACD)模型的方法,BALB/c小鼠35只,随机分为5组,分别为正常组,模型组和芒柄花素0.5,5,10 mg·kg^(-1)组,每组7只,在第1天,第2天用1.5%FITC溶液进行腹部致敏,每天1次,第6天用0.6%FITC溶液对小鼠右耳进行攻击。各组小鼠从致敏前2 d开始给予芒柄花素至第3天,每天1次,共5次(致敏初期预防给药),造模第6天攻击,攻击24 h后观察小鼠耳肿胀度及苏木素-伊红(HE)染色观察耳组织病理组织学变化,酶联免疫吸附测定(ELISA)方法检测耳组织匀浆中白细胞介素-4(IL-4),IL-5,IL-9的水平。结果:与正常组比较,模型组小鼠耳肿胀度显著增加,并有大量的淋巴细胞浸润(P<0.01),耳组织真皮层组织明显水肿,耳组织中IL-4,IL-5,IL-9水平显著升高(P<0.01);与模型组比较,致敏初期预防给予芒柄花素能明显减轻耳肿胀度,减少淋巴细胞浸润(P<0.05,P<0.01),减轻耳病理组织学改变,且不同程度地抑制耳组织中2型细胞因子IL-5,IL-9水平(P<0.05,P<0.01)。结论:发现了芒柄花素具有抑制过敏性炎症的新活性,其作用环节在致敏初期,且机制可能与抑制2型细胞因子的分泌有关。

Objective： To investigate the effect and preliminary mechanism of formononetin on allergic inflammation. Method： Th2 Type allergic contact dermatitis（ ACD） models were induced by fluoresciniso thiocyate（ FITC）. 35 BALB/c mice were randomly divided into normal group,model group,formononetin 0. 5,5,10 mg·kg^-1groups（ n = 7）. The mice were sensitized with 1. 5% FITC solution on day 1 and day 2 on the shaved abdomen skin,once a day. On day 6,the mice were challenged on their right ears with 0. 6% FITC solution. Formononetin was given to the mice from 2 days before sensitization to day 3 after sensitization,once a day for a total of 5 times（ prophylactical administration in initial sensitization period）; on day 6 of modeling,the mice were challenged on their right ears,and after 24 hours,ear swelling was observed and pathological changes of the ears were investigated by hematoxylin and eosin（ HE） staining. The levels of interleukin-4（ IL-4）,IL-5and IL-9 in homogenate of ear tissues were detected by enzyme-linked immunosorbent assay（ ELISA）. Result：As compared with the normal group,the ear swelling was significantly increased in mice of model group,with massive infiltration of lymphocytes（ P〈0. 01）; dermis tissues of the ears had obvious edema; IL-4,IL-5 and IL-9 levels in the ear tissues were significantly increased（ P〈0. 01）. As compared with the model group,prophylactical treatment with formononetin in initial sensitization period could significantly relieve the ear swelling and reduce lymphocytes infiltration（ P〈0. 05,P〈0. 01）,reduce the histopathological changes of ears,and inhibited type 2 cytokines IL-5 and IL-9 levels in the ear tissues to different degrees（ P〈0. 05,P〈0. 01）.Conclusion： Formononetin evidently inhibited allergic inflammation at the initial stage of sensitization,and its mechanism might be associated with inhibiting the secretion of type 2 cytokines.