甘草酸二铵调控糖皮质激素受体防治百草枯肺损伤机制：与TLRs信号通路相关？

Pulmonary fibrosis is the most prominent pathological process of lung injury by paraquat poisoning. The initial event of acute lung injury is alveolar epithelial cells (AEC) to start immunomodulatory and inflammatory response. Our preliminary studies confirmed that inflammation was out of control in the early paraquat poisoning, the intervention of hydrolase inhibitor can reduce the inflammation in lung tissue and improve the prognosis. We also found that Diammonium glycyrrhizinate (DG) can raise glucocorticoid receptor (GR) level in early lung injury and regulate a variety of immune factors, inflammatory cytokines' activity, but the mechanism in these process were not yet clear. Recent researches reported that GR would regulate TLRs signaling to effectively control the immune and inflammatory reaction. However, whether DG block lung injury induced by paraquat poisoning by interferencing the TLRs signaling? The intention of the study is to explore the expression of GR, TLRs signaling which regulated by DG in paraquat lung injury model of rats and GR-deficient mice; isolate and culture AEC, detect the expression of DG、GR, IL-17 and other regulatory pathways while blocked AEC by the TLRs inhibitors, investigate the relationship between GR and TLRs pathway; explore the mechanism of action between DG, GR and TLRs, provide a theoretical basis for the prevention and treatment of acute lung injury caused by paraquat poisoning.

肺纤维化是百草枯中毒肺损伤最为突出的病理过程，肺泡上皮细胞(AEC)启动免疫调节和炎症反应是肺损伤的起始事件。本项目组前期研究证实百草枯中毒早期即出现炎症反应失控，采用水解酶抑制剂干预能减轻肺组织炎症反应，并改善预后；发现甘草酸二铵（DG）可上调早期肺损伤糖皮质激素受体（GR）,并调控多种炎症细胞因子活性，但DG调控GR及炎症因子的具体机制尚未明确。最近研究报道GR可通过调节TLRs信号通路而有效控制机体自身免疫和炎症反应过程，DG是否通过此信号通路途径阻断百草枯肺损伤进程？本项目拟建立大鼠及GR缺陷小鼠百草枯肺损伤模型，探讨DG干预前后GR、TLRs通路表达情况；分离培养AEC，应用TLRs相关抑制剂阻断该通路，检测DG对GR、IL-17等调控情况，以初步揭示GR与TLRs通路之间的关系，进而阐明DG、GR及TLRs之间的作用机制，为临床防治百草枯中毒肺损伤提供一定的理论依据。

项目组前期研究发现甘草酸二铵（DG）可上调早期肺损伤糖皮质激素受体（GR）,并调控多种炎症细胞因子活性，但其具体机制尚未明确。本项目建立ALI大鼠动物模型，分离培养AEC，应用GR抑制剂干预，DG干预后检测GR、TLR4表达情况。结果证实DG可抑制PQ致ALI大鼠肺部TLR-4mRNA、NF-κBmRNA、血清IL-6、IL-17的过度表达，从而减轻ALI。AEC细胞实验证实DG可降低TLR-4、Myd88、NF-кB、TNF-α水平，并升高GR水平，减轻了百草枯诱导AEC细胞损伤。新建立百草枯肾损伤动物模型，发现DG可降低肾组织TLR-4、myd88及NF-κB的表达水平，其保护机制可能与降低血清和肾组织中IL‐6和IL‐17相关。已完成DG防治ALI的初步临床研究，项目在国内21家单位推广应用，受益病人2000例。已发表论文10篇，其中SCI论文3篇，获得省厅级科技成果一等奖1项，培养硕士研究生4名。项目已初步揭示甘草酸二铵可能通过TLRs通路调控GR与NF-кB进而而减轻百草枯肺损伤，为临床防治百草枯肺损伤提供坚实理论依据。