1,25-二羟维生素D_3对哮喘气道重塑小鼠模型NF-κB信号通路的调控研究

Regulatory effect of 1,25-(OH)_2D_3 on NF-κB signal pathway in asthmatic mice with airway remodeling

目的探讨1,25-二羟维生素D3[1,25-(OH)2D3]对慢性支气管哮喘(简称哮喘)小鼠气道重塑的干预作用及可能作用机制。方法 BALB/c小鼠随机分为对照组、哮喘组及VitD组。以卵白蛋白(OVA)致敏、反复激发9周(共31次)建立慢性哮喘气道重塑模型。VitD组在每次OVA激发前1 h予以腹腔注射100 ng 1,25-(OH)2D3。对照组用等量生理盐水代替OVA进行致敏和激发。末次激发后24 h处死小鼠。肺组织分别行HE染色和Masson染色,观察各组气道结构及上皮下纤维化,并用计算机图像分析系统评价各组气道重塑;蛋白免疫印记法检测肺组织核转录因子-κB(NF-κB)p65的核移位及IκBα、p-IκBα蛋白的表达水平;实时荧光定量(Real-time)PCR检测肺组织中IκBαmRNA表达水平。结果 (1)哮喘组出现炎性细胞浸润增多、上皮下纤维化及平滑肌细胞层增厚等气道重塑的结构改变,而1,25-(OH)2D3的干预可有效减轻上述病理改变;(2)1,25-(OH)2D3明显抑制哮喘肺组织中NF-κB p65的核移位;(3)1,25-(OH)2D3能通过上调IκBα的mRNA表达并抑制其磷酸化来上调哮喘肺组织中IκBα的蛋白表达。结论 1,25-(OH)2D3可通过负性调控NF-κB信号通路来拮抗哮喘气道重塑。

Aim To investigate the effect of 1,25-（OH）2D3 on airway remodeling in a murine model of chronic asthma and its underlying mechanism.Methods BALB/c mice were randomly divided into the control group,asthma group and VitD group（n=6）.The mice were sensitized to ovalbumin（OVA） and subsequently exposed to intranasal OVA challenge for 9 weeks（total 31 times） to establish the chronic asthmatic model.The mice in the VitD group received the intraperitoneal injection of 100 ng 1,25-（OH）2D3 1 h before each challenge.The mice in the control group were sensitized and challenged with PBS during the study.At the end of the exposure period,the mice were sacrificed and their lung sections were stained with HE and Masson＇s trichrome,respectively.Morphometric analysis of the stained sections was performed by computerized image analysis system.Nuclear translocation of NF-κB p65 was examined with western blot.And the level of IκBα was detected with real-time quantitative RT-PCR and western blot.The expression of its phosphorylated protein was also detected by western blot.Results（1） Prominent airway remodeling existed in the asthma group,including the infiltration of inflammatory cells,subepithelial collagen deposition and increased airway smooth muscle mass.But 1,25-（OH）2D3 attenuated these established structural changes of the airways.（2） 1,25-（OH）2D3 reduced the nuclear translocation of NF-κB in lung tissue of chronic asthma.（3） 1,25-（OH）2D3 increased the expression of IκBα mRNA with lesser phosphorylation of IκBα,and significantly increased the expression of IκBα in lung tissue of chronic asthma.Conclusions 1,25-（OH）2D3 can inhibit the NF-κB activity in lung tissue of chronic asthma,thus alleviating chronic asthma-induced airway remodeling.