Study On The Therapeutic Effect And Mechanism Of Panax Ginseng And Its Active Constituents On Lipopolysaccharide-induced Acute Lung Injury In Mice Based On TLR4/NF-κB/MAPK Signaling Pathway

Research background and purpose:Acute lung injury is a common critical disease in clinic with a high fatality rate,refered to diffuse interstitial and alveolar edema caused by various internal and external pulmonary factors.It seriously affects the quality of life of patients and increases economic burden of our society.Excessive inflammatory response is the most important pathogenesis of acute lung injury.Effector cells such as macrophages and neutrophils aggregate and release inflammatory factors and trigger a cascade of inflammatory cascades,resulting in the damaged tight junctions between alveolar epithelial cells and vascular endothelial cells.Thus,the permeability of alveolar capillary is increased,and protein-rich fluid in serum is permeated from capillaries to alveolar,leading to pulmonary edema,decreased lung compliance.The clinical manifestation of acute lung injury are refractory hypoxemia and progressive dyspnea.If the disease progresses,it can further develop into acute respiratory distress syndrome.Treatment of acute lung injury includes protective ventilation,fluid-restricted resuscitation,glucocorticoids,ibuprofen,risofylline,NO inhalation,alveolar surfactant,etc.Due to the limitation of efficacy and side effects,there is still a lack of safe and effective drugs,and it is imperative to develop novel therapeutic drugs.Previous studies have shown that panax ginseng has obvious anti-inflammatory and antioxidant effects.However,the active ingredients and underlying mechanisms of panax ginseng’s anti-inflammatory effect have been poorly elucidated.In addition,ginsenoside Ro and ginsenoside Rb3 are the main active components of panax ginseng.Many studies have shown that ginsenoside Ro and ginsenoside Rb3 have anti-inflammatory and antioxidant effects,and our previous studies displayed that they could inhibit the expression of inflammatory factors remarkably.Therefore,whether ginsenoside Ro and ginsenoside Rb3 are the material basis for the anti-inflammatory effects of panax ginseng?The purpose of this study is to clarify the therapeutical effect and mechanism of panax ginseng against lipopolysaccharide-induced acute lung injury through experiments in vitro and in vivo,and further explore the active components and material basis of panax ginseng for its anti-inflammatory effect.This study will provide a scientific basis for the clinical application of Traditional Chinese Medicine in treatment of acute lung injury and other inflammatory diseases.Methods:In animal experiments,intraperitoneal injection of lipopolysaccharide was utilized to establish acute lung injury model in sepsis mice.In cell experiments,lipopolysaccharide was utilized to stimulate mouse macrophage RAW264.7 cell line to induce inflammation model.HE staining,qPCR,ELISA,Western Blot,immunohistochemistry,immunofluorescence,and LPS binding were used to verify the inhibitory effect on lipopolysaccharide-induced lung tissue pathological injury,expression of inflammatory factors,and the regulation of TLR4 pathway of pananx ginseng and its active components.The interaction between TLR4 and ginsenoside Ro or ginsenoside Rb3,were further verified by molecular docking,molecular dynamics,surface plasmon resonance imaging,and LPS binding.Results:Animal experiments demonstrated that panax ginseng and ginsenoside Ro dose-dependently suppressed lipopolysaccharide-induced lung pathological injury,the expression of inflammatory factors and the activation of TLR4/NF-κB/MAPK pathway.Cell experiments showed that panax ginseng,ginsenoside Ro and ginsenoside Rb3 could significantly reduce the expression of inflammatory factors and the activation of TLR4/NF-κB/MAPK pathway stimulated by lipopolysaccharide in RAW264.7 cells.Molecular docking,molecular dynamics,surface plasmon resonance imaging and LPS binding indicated that ginsenoside Ro and ginsenoside Rb3 have excellent binding ability with TLR4/MD2,and ginsenoside Ro and ginsenoside Rb3 could directly target TLR4,acting as potential TLR4 inhibitors.Conclusions:Panax ginseng inhibits lipopolysaccharide stimulating inflammation and pathological changes in lung tissue by blocking the activation of TLR4/NF-κB/MAPK pathway,for which could protect mice from acute lung injury.Ginsenoside Ro and ginsenoside Rb3 are the effective components of panax ginseng to exert its anti-inflammatory role.