The Protective Effect And The Mechanism Of Myricetin On Sepsis-related Acute Lung Injury

Part One The clinical significance of plasma cytokines in patients withacute respiratory distress syndromeObjective: To observe the impact of biomarker groups on the classification and the prognosis of endogenous/exogenous ARDS.Methods: A total of 72 early ARDS patients who were treated in the critical care unints of the Second Hospital of Hebei Medical University from January 2019 to January 2021 were selected to collect relevant clinical data.Plasma concentrations of IL-6,IL-8,IL-10 and TNF-α were determined by the multiplex bead-based flow fluorescent immunoassay and were analyzed statistically.Results:1.There were differences between the two groups of patients with endogenous/exogenous ARDS in APACHAⅡ,SOFA score,and whether to use vasoactive drug on the first day,but there was no difference in mortality between the two groups.2.Compare with the endogenous ARDS,the concentrations of IL-6,IL-8,IL-10,TNF-α were statistically upregulated in exogenous ARDS group.3.For the whole group of ARDS,the increase of plasma IL-6 and IL-8concentration affected the prognosis of patients;the increase of plasma IL-6,IL-8 and IL-10 degree affected the prognosis of patients with exogenous pulmonary ARDS.4.The median of IL-8 and TNF-α had the potential to be used as a predictor of death risk.Conclusions: The clinical characteristics and concentrations of cytokines of patients with endogenous/exogenous ARDS were different.The elevated cytokines,such as IL-6、IL-8 and TNF-α,might affect the prognosis of patients.Part Two Myricetin’s anti-inflammatory and antioxidant effects onCLP-induced acute lung injuryObjective: To observe the effect of myricetin on the CLP-induced acute lung injury in mice,and to explore the mechanism.Methods: Aight-week-old male C57BL/6 mice were selected and randomly divided into sham group,sham + myricetin group,CLP group,and CLP+myricetin group.Pathological changes,dry-to-wet ratio,and inflammatory cell count in BALF were recorded.RT-q PCR was used to detected the m RNA expression of IL-1β,IL-6,TNF-α,and SOD1,SOD2,SOD3 in lung tissue,and ALISA method to IL-1β,IL-6,TNF-α,4-HNA in lung tissue.Western blotting was used to detect the concentration of Cytochrome C in and outside the nucleus.Immunohistochemical method was used to determine the expression levels of i NOS and COX2 in lung tissues.Flow cytometry was used to detect ROS and mitochondrial membrane potential.Commercial kits measured the levels of MDA,SOD,CAT,GSH-Px,ATP,Complex I and Complex III.Results:1.CLP could be competent for the sepsis-related ARDS mouse models.2.Myricetin alleviated the pathological manifestations of sepsis-related lung injury in mice,and relieved pulmonary vascular permeability and inflammatory cell response.3.Myricetin protected the lung of sepsis-related ARDS via anti-inflammatory effects.The expression of TNF-α,IL-1β and IL-6 in lung tissue and BALF,and the expression level of i NOS and COX-2 in lung tissue could be used as monitoring index.4.Myricetin protected the lung of sepsis-related ARDS by repairing the oxidation-antioxidate balance,which was found by reducing oxidation product and up-regulating antioxidant component.5.Myricetin improved mitochondrial function of lung tissue,maintained the integrity of the respiratory chain,and stabilized the mitochondrial membrane.Conclusions:Myricetin inhibited the excessive inflammatory response of mice lung injury induced by CLP,ameliorated oxidative stress and mitochondrial function,and protected lung of mice.Part Three Myricetin reduces CLP-induced lung injury through Nrf2related pathwaysObjective: To explore the protective mechanism of myricetin on the lung of mice with CLP-related lung injury.Methods: Aight-week-old male C57BL/6 mice were randomly divided into sham group,CLP group,and CLP+myricetin group,CLP+Myr+sh RNA-Nrf2 group,CLP+Myr+sh RNA-Con group.Pathological changes,pathological score,BALF inflammatory cell count were recorded.The level of Nrf2 m RNA in lung tissue was detected by RT-q PCR,the expression of Nrf2/HO-1 protein was detected by Western blotting,and Nrf2-DNA binding activity was determined by AMSA.The level of Nrf2 m RNA in lung tissue was detected by RT-q PCR,the expression of Nrf2/HO-1 protein was detected by Western blotting,and Nrf2-DNA binding activity was determined by AMSA.ALISA method was used to detect the concentration of IL-1β,IL-6,TNF-α in lung tissue.Commercial kits measured SOD,CAT and GSH-Px levels.Results:1.Myricetin could reduce the mortality of septic mice.2.Myricetin promoted the positive regulation of the Nrf2/HO-1 pathway and Nrf2-DNA binding activity in lung tissue of septic mice.3.The protective effect of myricetin on the lungs of septic mice was achieved through the reduction of inflammatory factors and the enhancement of antioxidant enzyme activity mediated by the Nrf2 pathway.Conclusions:Myricetin might regulate inflammatory factors and antioxidants in a Nrf2-dependent manner to reduce lung injury caused by sepsis.