miR-18a通过阻断TLR4/NF-κB通路减轻小鼠过敏性鼻炎的炎症和组织损伤

miR-18a ameliorates inflammation and tissue injury in a mouse model of allergic rhinitis via blocking TLR4/NF-kB pathway

目的探究微小RNA-18a(miR-18a)在小鼠过敏性鼻炎发病过程中的作用。方法22只BALB/c小鼠被随机分为空白组、模型组及miR-18a组。模型组和miR-18a组小鼠采用腹腔注射卵清蛋白(OVA)混悬液的方法制备过敏性鼻炎模型,miR-18a组小鼠同时给予过表达miR-18a的慢病毒载体质粒。采用行为学评分及HE染色评价各组小鼠过敏症状及形态学变化,ELISA检测血浆白细胞介素1β(IL-1β)、IL-6、肿瘤坏死因子α(TNF-α)水平,免疫荧光组织化学染色检测小鼠鼻黏膜组织CD45^(+)细胞浸润情况,流式细胞术检测鼻腔灌洗液CD45^(+)细胞数量,荧光定量PCR检测鼻黏膜组织IL-1β、IL-6、TNF-α的mRNA表达水平,Western blot法检测鼻黏膜组织Toll样受体4(TLR4)、核因子κB p65(NF-κB p65)、NF-κB抑制物α(IκBα)、磷酸化的IκBα(p-IκBα)的蛋白表达。结果与空白组相比,模型组小鼠血浆IL-1β、IL-6、TNF-α水平显著增高,鼻黏膜组织及鼻腔灌洗液CD45^(+)细胞数量增多,鼻黏膜组织IL-1β、IL-6、TNF-αmRNA水平及TLR4、NF-κB p65、p-IκBα表达水平升高;与模型组相比,miR-18a组小鼠血浆中IL-1β、IL-6、TNF-α水平显著降低,鼻黏膜组织及鼻腔灌洗液CD45^(+)细胞数量减少,鼻黏膜组织IL-1β、IL-6、TNF-αmRNA水平及TLR4、NF-κB p65、p-IκBα表达水平降低。结论miR-18a能够通过阻断TLR4/NF-κB通路抑制小鼠过敏性鼻炎的发生和发展。

Objective To investigate the role of microRNA-18a(miR-18a)in the pathogenesis of allergic rhinitis in mice.Methods Twenty-two BALB/c mice were randomly divided into a blank group,a model group and a miR-18a group.Mice in the model group and the miR-18a group were injected intraperitoneally with obumin(OVA)suspension to prepare allergic rhinitis models,and mice in the miR-18a group were simultaneously given lentiviral vector plasmid for overexpression of miR-18a.Allergy symptoms were evaluated by the behavioral score and HE staining.The plasma levels of interleukin-1β(IL-1β),IL-6 and tumor necrosis factorα(TNF-α)were measured by ELISA.The distribution of CD45+cells in nasal mucosa was measured by immunofluorescence histochemistry,and CD45^(+)cells in nasal lavage fluid were measured by flow cytometry.The mRNA expression levels of IL-1β,IL-6 and TNF-αin nasal mucosa tissues were measured by fluorescence quantitative PCR,and the protein expressions of Toll like receptor 4(TLR4),nuclear factor kB p65(NF-kB p65),inhibitor of NF-kBα(lkBa)and phosphorylated IkBα(p-lkBα)in nasal mucosa were measured by Western blot analysis.Results Compared with the blank group,the plasma levels of IL-1β,IL-6,and TNF-αin the model group increased significantly.The number of CD45^(+)cells in both nasal mucosa tissue and nasal irrigation fluid increased,and the mRNA levels of IL-1β,IL-6 and TNF-αand the protein expression levels of TLR4,NF-kB p65 and p-lkBαin nasal mucosa increased.Compared with the model group,the plasma levels of IL-1β,IL-6 and TNF-αin the miR-18a group decreased significantly.The number of CD45^(+)cells in both nasal mucosa tissue and nasal lavage fluid decreased,and the mRNA levels of IL-1β,IL-6 and TNF-αand the exprotein expression levels of TLR4,NF-kB p65 and p-lkBαin nasal mucosa decreased.Conclusion miR-18a can inhibit the occurrence and development of allergic rhinitis,and its molecular mechanism is related to the inhibition of TLR4/NF-kB pathwayactivation.