IL-4RA基因转染对哮喘模型的干预性作用研究

IL-4RA gene transfer by recombinant retroviral vector prevents the development of experimental asthma

目的IL-4RA基因转染对哮喘模型过敏性炎症的干预性研究。方法选择雌性BALB／c小鼠作为动物模型，随机分为5组（每组10只）：空白对照组、哮喘模型组、空载体（10^4CFU/ml pLNC-laz）干预组、激素治疗组、目的基因（10^4CFU/ml pLNC-IL-4RA）干预组。各组在最后一次激发后24h放血杀死小鼠，检测血中嗜酸性粒细胞（eosinophils，EOS）计数，用ELISA检测支气管肺泡灌洗液（broncho alveolar lavage fluid，BALF）中的各种细胞因子水平，并对BALF中各种炎症细胞计数，肺组织切片做HE染色。结果哮喘模型鼠BALF中有大量嗜酸性粒细胞浸润，肺组织病理切片可见大量炎症细胞浸润、杯状细胞增生、黏膜壁破坏。哮喘模型的这些改变在激素和基因干预后明显减轻，差异有统计学意义（P〈0．01），而在空载体干预后则无明显的变化（P〉0．05）。空白对照组的BALF中IL-5、IL-13低于检测水平，哮喘模型组BALF中IL-5、IL-13水平明显增高，而基因治疗组和激素治疗组IL-5、IL-13水平明显减少，差异有统计学意义（P〈0．01），空载体干预组BALF中细胞因子水平与哮喘模型组比较差异无统计学意义（P〉0．05）。结论通过逆转录病毒转染的IL-4RA的基因高表达成功地阻止在哮喘模型鼠气道由Ⅱ，4和IL-13诱发的气道嗜酸性粒细胞浸润，另外，逆转录病毒介导的IL-4RA在气道的表达明显地阻止了哮喘模型气道黏液的分泌，同时也减少了过敏性哮喘相关的TH2细胞因子水平，因此，基因治疗可能会成为治疗慢性哮喘气道炎症和哮喘症状的极有潜力的药物。

Objective To study the effect of IL-4RA gene transfer to the airways of asthmatic mice on the inflammation. Methods Female BALB/c mice were divided into 5 groups randomly （ 10 per group） ： blank control, asthma model, asthma model administered by 10^4 CFU/ml pLNC-laz, asthma model by glucocorticoid, and asthma model by 10^4 CFU/ml pLNC-IL-4RA. 24 h after the last challenge, mice were killed by bloodletting, and haemal eosinophils were counted. Cytokine levels in the broncho alveolar lavage fluid （BALF） were measured by ELISA. The number and type of inflammation cells in BALF were assessed. Histological sections of lungs were prepared and stained with HE. Results Large number of eosinophils infiltrated in BALF and serum of asthma model, lots of infiltration inflammatory cells were detected in pneumonic tissue sections, with cap-shaped cell hy-perplasia and broken mucus membrane. These changes were significantly alleviated in asthma models treated with glucocorticoid and models with pLNC-IL-4RA （P〈0.01）, and no significant change was found in models with pLNC-laz （P〉0.05）. Administration of pLNC-IL-4RA or glucocorticoid significantly inhibited the elevation of IL-5 and IL-13 levels in BALF of asthmatic mice, while administration of pLNC-laz had no significant effect on BAI2 cytokine levels of asthmatic mice （P〉 0.05）. Conclusion Retrovirus mediated delivery of IL-4RA to airways of mice reduced infiltration of eosinophils in airways triggered by either IL-4 or IL-13. Furthermore, IL-4RA delivered by retrovirus, expressed in the airways of mice following allergen sensitization, significantly inhibited development of airways mucus production and reduced the level of asthma-associated TH2 cytokines in the experimental mouse of allergic asthma. Thus, gene therapy can be a potential therapeutic option to treat and control chronic airways in- flammation and asthmatic symptoms.