Cong Cuicui, Mao Lijun, Zhang Yanlin, Zhao Zanmei, Xu Xixian, Zhao Jinyuan
Occupational Disease Department, Peking University Third Hospital, Beijing, China.
Exp Lung Res. 2014 Sep;40(7):317-26. doi: 10.3109/01902148.2014.920438. Epub 2014 Jun 13.
Silicosis is a serious occupational disease characterized by lung fibrosis that is caused by long-term inhalation of silica-containing fine particles. Lysophosphatidic acid (LPA) and LPA1/3 plays a role in lung fibrosis. Until recently, there has been little research investigating the role of LPA and LPA receptors (LPAR) in silica-induced development of pulmonary fibrosis. In this study, we evaluated the hypothesis that LPA and LPA1/3 may play a role in silicosis pathogenesis using rat silicosis models induced by intratracheal instillation of silica, and randomly divided into control, silica, and VPC-12249 groups. LPA serum and bronchoalveolar lavage fluid (BALF) levels were quantified by ELISA. α-smooth muscle actin (α-SMA), type I and III collagen protein expression was quantified by western blotting (WB), and type I and III collagen mRNAs detected by reverse transcriptase-polymerase chain reaction (RT-PCR). Lung hydroxyproline (HYP) levels were detected using alkaline hydrolysis, with hematoxylin and eosin (H&E) and picrosirius red staining used for pathological examination. In vitro experiments showed that LPA stimulated fibroblasts proliferated in a time and dose-dependent manner and promoted expression of α-SMA, and type I and III collagen. Moreover, LPA serum and BALF levels increased in silica-instilled rats. In vivo and in vitro experiments revealed that α-SMA expression and collagen deposition reduced significantly after VPC-12249 treatment, and histopathological results show VPC-12249 alleviates silicosis progression. In conclusion, our findings suggest that LPA promotes the proliferation, transformation, and collagen synthesis of fibroblasts, and that LPA-LPA1/3 are involved in the development of silicosis and may serve as novel therapeutic targets for treatment.
矽肺是一种严重的职业病，其特征是长期吸入含二氧化硅的细颗粒导致肺纤维化。溶血磷脂酸（LPA）和LPA1/3在肺纤维化中起作用。直到最近，关于LPA及其受体（LPAR）在二氧化硅诱导的肺纤维化发展中的作用的研究还很少。在本研究中，我们使用气管内注入二氧化硅诱导的大鼠矽肺模型评估了LPA和LPA1/3可能在矽肺发病机制中起作用的假设，并将其随机分为对照组、二氧化硅组和VPC-12249组。通过酶联免疫吸附测定（ELISA）对血清和支气管肺泡灌洗液（BALF）中的LPA水平进行定量。通过蛋白质免疫印迹法（WB）对α平滑肌肌动蛋白（α-SMA）、I型和III型胶原蛋白的蛋白表达进行定量，并通过逆转录聚合酶链反应（RT-PCR）检测I型和III型胶原蛋白的mRNA。使用碱性水解法检测肺组织羟脯氨酸（HYP）水平，并用苏木精-伊红（H&E）染色和天狼星红染色进行病理检查。体外实验表明，LPA刺激成纤维细胞增殖呈时间和剂量依赖性，并促进α-SMA以及I型和III型胶原蛋白的表达。此外，注入二氧化硅的大鼠血清和BALF中的LPA水平升高。体内和体外实验表明，VPC-12249治疗后α-SMA表达和胶原蛋白沉积显著减少，组织病理学结果显示VPC-12249可缓解矽肺进展。总之，我们的研究结果表明，LPA促进成纤维细胞的增殖、转化和胶原蛋白合成，并且LPA-LPA1/3参与矽肺的发展，可能成为新的治疗靶点。
