The Role Of Hydrogen Sulfide In Relieving Diaphragm Dysfunction By Lipopoiysaccharide

Background The diaphragm is the main respiratory muscle.It is recognized as the primary muscle of respiration that contributes 60-80% of respiratory function,so it is vital to maintain respiration.Diaphragm dysfunction is an important clinical problem in the world,but its incidence and influence are often ignored,and the prevention and treatment measures are few.Studies have confirmed that infection is a major risk factor for diaphragm dysfunction in critically ill patients,and sepsis can induce diaphragmatic dysfunction.Lipopolysaccharide is one of the cell wall components of most Gram-negative bacteria.Recently,LPS has been widely adopted to induce septic diaphragm dysfunction in many different animal models.Hydrogen sulfide has been considered as the third gaseous signaling molecule after nitric oxide and carbon monoxide,and is widely involved in the physiological and pathological processes in mammals.It possesses anti-inflammatory,anti-apoptotic,anti-oxidative,regulate ion channels,protect cardiovascular and other effects,and plays an important regulatory role in the respiratory system.At present,there are few reports on H2 S and diaphragm dysfunction.Recently,it was first discovered that H2 S exerts an important cytoprotective effect on sepsis-induced diaphragm dysfunction and increases the survival rate of sepsis rats,but its mechanism needs to be further elucidated.L6 cells were applied to the study of diaphragm in vitro.On the basis of the previous research results of our group,we treated L6 cells with LPS and explored the effect of H2 S on LPS-induced L6 cells.At the same time,we used LPS to construct sepsis rat models to study the effect of exogenous H2 S on diaphragm dysfunction and tissue structure,and to explore the associated molecular mechanism.Objective L6 cells were treated with LPS to study the effects of H2 S on proliferation,apoptosis,anti-inflammatory and anti-oxidation of L6 cells induced by LPS.At the same time,we used LPS to construct sepsis rat models to further determined the effect of exogenous H2 S on diaphragm dysfunction and clarified the associated molecular mechanism,in order to provide clinical treatment for infectious diaphragm dysfunction.MethodsWe stimulated L6 cells with LPS,and the proliferation and apoptosis of L6 cells in control,LPS and LPS + H2 S groups were detected by MTS,Ed U and Tunel methods;the level of reactive oxygen species(ROS)and the activity of catalase,superoxide dismutase and glutathione peroxidase in each group were detected by kit;the expression of apoptosis-related signaling pathway,MAPK and NF-?B signaling pathway-related proteins in each group were detected by western blotting;the expression of inflammatory factors in each group were detected by ELISA kit;construct sepsis rat model to study the effect of exogenous H2 S on diaphragm mechanical index and tissue structure.Results1.The level of H2 S in the LPS-treated L6 cells and supernatants is significantly reduced and treatment with H2 S significantly increased the viability and proliferation of LPS-treated L6 cells.2.H2 S could decrease ROS-induced apoptosis through MAPK signaling pathway in LPS-treated L6 cells.3.H2 S could alleviate LPS-induced inflammation by mediating the TLR-4/NF-?B signaling pathway in L6 cells.4.H2 S can improve diaphragmatic muscle function and tissue structure by alleviating the inflammation and apoptosis of diaphragmatic muscle in septic rats.Conclusion H2 S may be involved in the ROS / MAPK and TLR4 / NF-?B signal transduction pathway,which ameliorates the diaphragm dysfunction induced by LPS by reducing apoptosis and inflammation in rats.