Ding Wei, Zhang Xing-Yi, Pan Ming, Zhao Bin, Chen Chuang, Niu Zhi-Hao, Huang Cheng-Liang, Li Yan-Yan, Fan Xian-Ming, Ma Yan-Mei, Zhang Ming, Zhang Wen-Jun
Department of General Surgery, Second Hospital, Jilin University, Changchun, Jilin 130022, P.R. China.
Department of Respiratory Medicine, The Affiliated Hospital of Luzhou Medical College, Luzhou, Sichuan 646000, P.R. China.
Exp Ther Med. 2015 Aug;10(2):491-497. doi: 10.3892/etm.2015.2564. Epub 2015 Jun 10.
The aim of the present study was to investigate the effects of interleukin (IL)-17A in a rat model of pulmonary fibrosis. In total, 20 female Wistar rats were randomly divided into a normal saline (NS group) and a bleomycin group (BLM group). The BLM group rats were intratracheally instilled with BLM, while the NS group rats were intratracheally instilled with saline. In each group, half the rats were sacrificed at day 7 and day 28, respectively, following intratracheal instillation. Subsequently, hematoxylin and eosin and Masson's trichrome staining were performed to observe the pathological changes in the lung tissue, while the expression of IL-17A in the lung tissue was detected by immunohistochemistry. In addition, the bronchoalveolar lavage fluid (BALF) was collected and divided into two sections. One section was used for cell counting and classification, and an ELISA was performed to detect the concentration of IL-17A in the BALF. The additional section was used to separate, purify and cultivate alveolar macrophages (AMs). The concentration of IL-17A in the cultivating supernatant was detected by ELISA, and the mRNA expression levels of IL-17A in the AMs were detected using reverse transcription-polymerase chain reaction (RT-PCR). The results revealed that a considerable number of inflammatory cells had infiltrated into the alveolar cavity in the BLM group at day 7, and less alveolitis and more serious fibrosis were observed at day 28, as compared with the NS group. Furthermore, when compared with the NS group, the protein expression levels of IL-17A in the lung tissue were markedly higher in the BLM group at days 7 and 28 (higher at day 7; P<0.05). In addition, the total number of BALF cells in the BLM group was clearly higher at day 7 when compared with the NS group (P<0.05), although a normal level was re-established by day 28. The level of IL-17A in the BALF increased significantly at days 7 and 28 in the BLM group; however, when compared with the level at day 7, the concentration had decreased at day 28. When compared with the NS group, the protein expression levels of IL-17A in the BLM group were notably higher after 12, 24 and 48 h. In addition, the results of the RT-PCR assay revealed that the mRNA expression levels of IL-17A increased significantly at days 7 and 28 in the BLM group when compared with the NS group (P<0.05). Therefore, IL-17A was demonstrated to promote the development of pulmonary inflammation, which may be involved in the development of pulmonary fibrosis.
本研究的目的是在大鼠肺纤维化模型中研究白细胞介素（IL）-17A的作用。总共20只雌性Wistar大鼠被随机分为生理盐水组（NS组）和博来霉素组（BLM组）。BLM组大鼠经气管内注入博来霉素，而NS组大鼠经气管内注入生理盐水。每组中，分别在气管内注入后第7天和第28天处死一半大鼠。随后，进行苏木精-伊红染色和Masson三色染色以观察肺组织的病理变化，同时通过免疫组织化学检测肺组织中IL-17A的表达。此外，收集支气管肺泡灌洗液（BALF）并分为两部分。一部分用于细胞计数和分类，并进行酶联免疫吸附测定（ELISA）以检测BALF中IL-17A的浓度。另一部分用于分离、纯化和培养肺泡巨噬细胞（AM）。通过ELISA检测培养上清液中IL-17A的浓度，并使用逆转录-聚合酶链反应（RT-PCR）检测AM中IL-17A的mRNA表达水平。结果显示，与NS组相比，BLM组在第7天有大量炎性细胞浸润到肺泡腔，在第28天观察到肺泡炎减轻但纤维化更严重。此外，与NS组相比，BLM组在第7天和第28天肺组织中IL-17A的蛋白表达水平明显更高（第7天更高；P<0.05）。另外，与NS组相比，BLM组在第7天BALF细胞总数明显更高（P<0.05），尽管在第28天恢复到正常水平。BLM组在第7天和第28天BALF中IL-17A水平显著升高；然而，与第7天的水平相比，第28天浓度有所下降。与NS组相比，BLM组在12、24和48小时后IL-17A的蛋白表达水平明显更高。此外，RT-PCR检测结果显示，与NS组相比，BLM组在第7天和第28天IL-17A的mRNA表达水平显著升高（P<0.05）。因此，IL-17A被证明可促进肺部炎症的发展，这可能参与了肺纤维化的发展。
