1,25-二羟维生素D2减轻哮喘小鼠的气道重塑

摘要

目的 探讨1,25-二羟维生素D3(1,25(OH)2D3,VD)对哮喘小鼠气道重蝮及其肺组织中基质金属蛋白酶-9(MMP-9)表达的干预作用及其机制.方法 建立慢性哮喘小鼠模型,将小鼠随机分为对照组、哮喘组、地塞米松(DEX)组及VD组.HE染色观察各组气道结构;用计算机图像分析系统评价各组气道重蝮;用明胶酶谱法及RT-PCR法检测各组的MMP-9的活性及其mRNA表达.结果 (1)哮喘组出现炎性细胞浸润增多、上皮细胞脱落及平滑肌细胞层增厚等气道重塑改变,而DEX组及VD组均可部分逆转上二述病理改变;(2)DEX组及VD组的支气管内壁厚度、平滑肌层厚度和平滑肌细胞核数显著低于哮喘组,但仍高于对照组(P<0.05);(3)DEX组及VD组肺组织MMP-9的活性分别为对照组的(2.24±0.16)倍及(3.46±0.09)倍,而哮喘组是对照组的(7.87±0.09)倍(P<0.05);(4)各组MMP-9 mRNA相对定量分别为对照组(0.57±0.08)、哮喘组(5.74±0.13)、DEX组(2.63±0.11)及VD组(3.16±0.09),且两两比较均P<0.05.结论 1,25(OH)2D3可显著减轻哮喘气道重塑的病理改变;并可通过部分抑制肺内MMP-9的表达来延缓气道重塑进程.%Objective To investigate the effects of 1,25 (OH)2D3 on airway remodeling and the expression of matrix metalloprotease-9( MMP-9 ) in a murine model of chronic asthma, and to explore the potential mechanism of 1,25 (OH) 2 D3 in the treatment of asthma. Methods BALB/c mice were sensitized and challenged with ovalbumin to establish the chronic asthmatic model. They were randomly divided into control group, asthma group, dexamethasone (DEX) group and VD group. The characteristic airway inflammation and alteration of airway structure were detected by HE staining. Morphometric analysis of the stained sections was performed using computerized image analysis system. The expression of MMP-9 in both activity and mRNA level was detected by gelatin zymograph and RTPCR, respectively. Results ( 1 ) The infiltration of inflammatory cells, epithelial loss, smooth muscle cell layer thickening were decreased in DEX group and VD group when compared with those in asthma group( P ＜0.05 ), but these changes were both more significant than those in the control group(P ＜ 0. 05 ); (2)WAr/Pbm 、WAi/Pbm and N/Pbm decreased significantly in VD group when compared with those in asthma group( P ＜ 0. 05 ), but they were still higher than those in the control group (P ＜0. 05); (3)Stimulation with asthmatic serum induced a 7. 873-fold increase in the MMP-9 activity compared with that in the control group, and pretreatment with DEX or VD only induced a 2. 238-fold or 3. 460-fold increase in the MMP-9 activity compared with that in the control group (P ＜0. 05);(4) The mRNA level of M MP-9 in VD group(3. 16±0. 09) and DEX group (2. 63 ±0. 11 ) was decreased when compared with those in asthma group (5. 74 ± 0. 13 ) ( P ＜ 0. 05 ), but it was still higher than those in the control group(0. 57 ±0. 08) (P ＜0. 05). Conclusion Intervention with 1,25(OH)2D3 could markly alleviate the asthmatic airway remodeling and partly restore of appropriate structure of airway wall. It could also lower the expression of MMP-9 in the lung tissue on asthmatic condition ,thus delay the process of airway remodeling.