目的探讨1,25-二羟维生素D3[1,25-(OH)2D3]对慢性哮喘小鼠气道重塑模型肺组织中基质金属蛋白酶9(MMP-9)表达及核转录因子κB(NF-κB)活化的影响。方法 BALB/c小鼠随机分为对照组、哮喘组及VD组。卵白蛋白(OVA)致敏、激发建立慢性哮喘气道重塑模型。HE染色及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NF-κB p65的核移位;蛋白免疫印记法和实时荧光定量PCR(RT-PCR)法检测IκBα的表达水平;明胶酶谱法及RT-PCR法检测MMP-9的活性及mRNA表达。结果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。VD组肺组织MMP-9活性为对照组的(3.46±0.57)倍,而哮喘组为对照组的(7.87±0.89)倍(P〈0.05);VD组MMP-9 mRNA相对含量为(3.16±0.09),显著低于哮喘组(5.74±0.13)(P〈0.05),但仍高于对照组(0.57±0.08)(P〈0.05)。1,25-(OH)2D3显著抑制哮喘肺组织中NF-κB p65的核移位并上调IκBα的表达。结论 1,25-(OH)2D3能抑制哮喘肺组织中NF-κB的活化并减少MMP-9表达,进而干预慢性哮喘气道重塑过程。
Objective To investigate the effects of 1,25-(OH) 2 D3 on the expression of matrix metalloprotease-9 (MMP-9) and nuclear factor KB (NF-KB) activity in a murine model of chronic asthma. Methods BALB/c mice were sensitized and challenged with ovalbumin to establish chronic asthmatic model. The animals were randomly divided into a control group, an asthma group and a VD group. Lung sections from the mice were stained by HE and Masson' s trichrome, respectively. Morphometric analysis of the stained sections was performed using computerized image analysis system. Nuclear translocation of NF-tcB p65 was examined using Western blot. The level of IKBct was detected with real-time quantitative PCR ( RT- PCR) and Western blot. In addition, the expression of MMP-9 in both activity and mRNA level was detected by gelatin zymograph and RT-PCR, respectively. Results Prominent airway remodeling developed in the asthma group, including the inflammatory cell infiltration, subepithelial collagen deposition and increased airway smooth muscle mass. In contrast, 1,25-(OH) 2D3 attenuated these established structural changes of the airways. Stimulation with OVA induced a 7.87-fold increase in the MMP-9 activity compared with that in the control group,and 1,25-( OH)2D3 treatment only induced a 3.46-fold increase in the MMP-9 activity compared with that in the control group (P 〈0. 05). The mRNA level of MMP-9 in the VD group (3.16 + 0. 09) was decreased compared with the asthma group (5.74 +0. 13) (P〈0. 05) ,but it was still higher than that in the control group ( O. 57 ± 0. 08 ) ( P 〈 0. 05 ). 1,25- (OH) 2 D3 reduced the nuclear translocation of NF-KB p65 while up-regulated the IKBct level in lung tissue of chronic asthma. Coneluslons 1,25- (OH)2D3 can inhibit the NF-KB activity and down-regulate the expression of MMP-9 in lung tissue of chronic asthma, thus alleviating the established chronic asthma-induced airway remodeling.