哮喘豚鼠下呼吸道MMP-2的表达及NGF的调节作用

目的探讨基质金属蛋白酶-2(MMP-2)在哮喘豚鼠下呼吸道的表达及神经生长因子(NGF)对MMP-2的调节作用。方法应用免疫组织化学方法检测各组豚鼠下呼吸道MMP-2免疫反应的变化。用W estern b lot蛋白印迹方法检测各组豚鼠肺组织NGF和MMP-2的表达。用Luzex-F实时图像分析系统和凝胶成像分析系统分别对结果进行图像分析。结果①免疫组织化学结果显示:豚鼠气道上皮和肺内炎性细胞的MMP-2阳性免疫反应产物的平均灰度值(0-深色,255-浅色),生理盐水组(185.60±4.81、161.47±5.71)与单纯致敏组(184.80±9.64、160.33±4.03)比较没有显著差异(P>0.05);哮喘组(141.93±4.66、129.77±4.07)明显低于生理盐水组和单纯致敏组(P<0.01);哮喘+NGF抗体组(鼻腔吸入NGF抗体,179.73±6.11、150.23±8.13)则明显高于哮喘组(P<0.01)。②W estern b lot结果显示:与生理盐水组和单纯致敏组比较,哮喘组豚鼠肺组织MMP-2和NGF阳性产物的IDV(Integrated Density Value)与β-actin IDV的比值均明显升高(P<0.01),而哮喘+NGF抗体组则明显低于哮喘组(P<0.01),表明NGF可上调MMP-2的表达。结论MMP-2可能是哮喘气道重塑的一种调控因素,NGF诱发MMP-2的表达可能是NGF参与哮喘发病的机制之一,NGF抗体抑制哮喘时下呼吸道MMP-2的表达有可能延缓气道重塑的发生,可能是治疗哮喘的新途径。

Expression of MMP-2 and the Regulatory Effect of NGF in the Lower Respiratory Tract of the Asthmatic Guinea Pig

Objective To explore the expression of matrix metalloproteinase-2(MMP-2) and the regulatory effect of nerve growth factor(NGF) in the lower respiratory tract of the asthmatic guinea pig.Methods The changes of MMP-2 immunoreactivity were investigated by means of immunohistochemistry in lower respiratory tract of the guinea pigs in different groups.The expressions of NGF and MMP-2 were observed by Western blot in the lung of all the groups.The results were analyzed by the Luzex-F real time image analysis system and the gel imaging analysis system respectively.Results ①Immunohistochemistry results showed that there was no obvious difference for the mean grey values(0-black to 255-white) of MMP-2 positive products in the airway epithelia and the pulmonary inflammatory cells between normal saline control group(185.60±4.81,161.47±5.71) and simply sensitized group(184.80±9.64,160.33±4.03)(P>0.05).The mean grey values of MMP-2 positive products decreased significantly in the lower respiratory tract(141.93±4.66,129.77±4.07)of the asthmatic guinea pigs compared with the normal saline control group and the simply sensitized group(P<0.01).However,the mean grey values were much higher in NGF antibody group(inhalation of NGF antibody into nasal cavity,179.73±6.11,150.23±8.13) than inasthmatic group(P<0.01).②Western blot results showed that: compared with normal saline control group andsimply sensitized group,the ratios between Integrated Density Value(IDV) for MMP-2 or NGF protein band and IDVforβ-actin protein band increased markedly in the lung of asthmatic group(P<0.01),however,the ratios of NGFantibody group reduced markedly in comparison with asthmatic group(P<0.01),indicating that NGF can upregu-late the expression of MMP-2.Conclusions MMP-2 might play a role in airway remodeling in asthma,the overex-pression of MMP-2 induced by NGF might be one of the mechanisms for the involvement of NGF in the pathogenesisof asthma,and inhibitory expression of MMP-2 by NGF antibody in the lower respiratory tract might inhibit airway re-modeling and be a new route for the prevention and treatment of the bronchial asthma.