端粒长度变化在大棚肺小鼠发病机制中作用探讨

Greenhouse lung disease (GLD) belongs to hypersensitivity pneumonitis, has become one of the major diseases threatening health among greenhouse farmers. According to the pathological changes, greenhouse lung disease can be divided into acute stage infiltrating with peribronchovascular mononuclear cell, subacute stage with granuloma formation and may eventually develop into the chronic pulmonary fibrosis disease duration. Peribronchiolar fibrosis can be identified in most of the end-stage patients with chronic farmer's lung disease, the prognosis is poor, and the 5-year survival rate is low, similar with IPF in imaging findings and pathologic characteristics. Telomeres are specialized nucleoprotein structures TTAGGG that protect chromosomal ends in the cell division. It has been found that patients with idiopathic pulmonary fibrosis (IPF) had shorter telomere lengths than controls. There are findings suggest that shorter leukocyte telomere lengths are associated with worse survival in IPF. So, we try to hypothesize that the end-stage farmer's lung affected individuals have shorter telomere than controls. We have successfully made farmer's lung mice by ultrasonic atomizing inhalation and intranasal instillation of streptomyces thermohydroscopicus in the former work. We intend to isolate epithelial cells of lungs in farmer's lung mice, and extract DNA from the epithelial cells of lungs, measure the telomere length by quantitative PCR and flow cytometry and flow fluorescence in situ hybridization, aim to understand the role of telomere in pathogenesis of farmer's lung mice.

大棚肺属于过敏性肺炎，已成为威胁大棚从业农民健康的主要疾病之一。大棚肺按病理改变可分为支气管血管周围单核细胞浸润的急性期、肉芽肿形成的亚急性期以及可能最终发展成肺纤维化病变的慢性持续期，肺纤维化常是慢性大棚肺的终末期表现，与特发性肺纤维化终末期的影像病理表现类似，其临床治疗疗效差，5年生存率低。端粒是DNA双螺旋末端的一段TTAGGG高度重复的碱基序列，在细胞分裂过程中具有保护线粒体末端的作用。目前已有研究发现特发性肺纤维化病人比对照组的端粒短，且提示端粒长度更短的特发性肺纤维化病人生存率更差。因此，可以提出假说：大棚肺终末期患病个体端粒长度较对照组更短。我们课题组前期已经成功利用雾化吸入和鼻内滴入嗜热吸水链霉菌诱导出大棚肺动物模型。本课题拟在前期研究基础上，分离提取大棚肺小鼠肺组织上皮细胞及DNA，利用定量PCR及流式荧光原位杂交方法检测端粒长度，探讨端粒在大棚肺小鼠发病机制中的作用。

大棚肺属于过敏性肺炎，已成为威胁大棚从业农民健康的主要疾病之一。大棚肺按病理改变可分为支气管血管周围单核细胞浸润的急性期、肉芽肿形成的亚急性期以及可能最终发展成肺纤维化病变的慢性持续期，肺纤维化常是慢性大棚肺的终末期表现，与特发性肺纤维化终末期的影像病理表现类似，其临床治疗疗效差，5年生存率低。端粒是DNA双螺旋末端的一段TTAGGG高度重复的碱基序列，在细胞分裂过程中具有保护线粒体末端的作用。已有研究发现特发性肺纤维化病人比对照组的端粒短，且提示端粒长度更短的特发性肺纤维化病人生存率更差。本项目综合预选所有大棚土壤中的分离菌株，筛选出最常见细菌并构建其cDNA文库，鉴定出与免疫反应相关的基因，并对这些基因进行体外表达、纯化后得到高纯度蛋白抗原；同时，成功建立大棚肺小鼠模型，评价大棚肺小鼠和对照小鼠的特异性及敏感性，获得特异性和敏感性较高的抗原，用单一的高特异性抗原诱导致大棚肺动物模型，观察动物模型病理变化情况。最终，运用qPCR及Flow FISH方法检测基因组端粒长度，结果显示大棚肺小鼠端粒长度较对照组明显缩短，提示端粒功能机制可能参与到大棚肺的发病机制中。