大鼠β-防御素-2基因气道转染增强肺抗感染防御功能的研究

β-防御素体外试验显示具广谱抗菌活性，本研究应用转基因方法评估其体内抗菌作用。构建大鼠β-防御素-2(rBD2)重组质粒pBK-CMV-rBD2和pCDNA-3．1-Myc-His( )-rBD2，通过脂质体包裹的方法将重组质粒经气管滴入，检测其在气管和肺组织表达情况，并应用肺组织匀浆上清菌落计数法检察对绿脓杆菌的肺清除率。结果显示在基因转染大鼠的气管和肺组织内均检测到rBD2-His融合蛋白基因mRNA和蛋白的表达，说明脂质体包裹的重组p防御素-2pBK-CMV-rBD2质粒可有效转染气道上皮组织。肺细菌清除率实验显示构建重组质粒pBK-CMV-rBD2气道转染与对照相比可显著提高肺组织对绿脓杆菌的清除率(n(8，p(0．01)．本研究表明β-防御素基因气道转染可提高呼吸道天然抗感染防御功能，可能在呼吸道感染的防治实践中具有潜在应用价值。

Airway β-defensin-2 Gene Transfer Enhances the Bacterial Clearing of Rat Lung

beta-defensins possess a broad spectrum of antimicrobial activity. In this study its in vivo antibacterial effect was evaluated by using gene transfer. Rat beta-defensin-2 (rBD2) recombinant pBK-CMV-rBD2 and pCD-NA-3, 1-Myc-His(+)-rBD2 were constructed. Then, by use of liposome agent, the recombinants were delivered into rat airway via tracheal injection. The rBD-2 mRNA expression was detected in the trachea by RT-PCR and its protein expression was determined in the lungs by the tag His immunostaining, 24 hours after inoculation via trachea, the count of P. areuginosa in the lung of rat transfected with pBK-CMV-rBD2 markedly decreased, compared with the control (n = 8, P = 0.003). The data presented in this study provide evidence that airway beta-defensin-2-gene transfer can protect the rat against bacterial infection in vivo, suggesting the beta-defensins as part of the innate host defense system can be of potential applicability.