Preliminary Study On Synergism Between Indomethacin And Ciprofloxacin In The Treatment Of Severe Trauma Infection And Its Cytological Mechanism

With the advancement of prehospital and hospital emergency care technology,the first and second peaks of death caused by severe trauma have been effectively curbed,and various complications caused by infection have become the main cause of late death(third peak of death)in severe trauma casualties.Invasion of pathogenic microorganisms,excessive inflammatory response and immune dysfunction are important events in the development of severe trauma complications.Current clinical treatment practice often emphasizes the use of antibiotics and treats effective bacterial killing as the primary means of treating patients with severe trauma infections,but to some extent ignores the impact of excessive inflammatory response on trauma casualties.In fact,the endotoxin and exotoxin released by the dead bacteria can trigger excessive inflammation response,which will aggravate the condition of the injured person and lead to sepsis,multiple organ dysfunction syndrome(MODS),and finally multiple organ failure(MOF)and death.Therefore,the "bacteria-toxin-inflammatory mediator" strategy has become a new idea in the field of trauma medicine and critical care medicine to prevent and treat severe trauma complications.Nonsteroidal anti-inflammatory drugs(NSAIDs)are a class of drugs with a nonsteroidal structure that combine antipyretic,analgesic,anti-inflammatory,and antirheumatic effects.Although NSAIDs have been widely used in clinical practice,they were not originally intended to be used for anti-inflammatory reasons,but mostly for their analgesic function.As the classic representative of NSAIDs,indomethacin(IND)has 10～40times stronger anti-inflammatory effect than aspirin,and is cheap and easy to promote.On the other hand,ciprofloxacin(CIP)is the most widely used fluoroquinolone antibiotic in the world,with a broad antibacterial spectrum,strong antibacterial activity,low toxic side effects and low cost.In addition,as the main type of natural immune cells,macrophages can modulate the excessive inflammatory response of the body through polarity switching,thus affecting the course of severe trauma complications.The previous work of our team has confirmed that the combination of IND and CIP can promote local wound repair and enhance the immune function of the body.However,the efficacy and safety of the combination of the two drugs on the infection-mediated complications of severe trauma are still unclear,and there are no studies on the relevant target cells and molecular mechanisms reported.Therefore,this study proposes the scientific hypothesis that "IND combined with CIP after severe trauma infection can control inflammation and infection,prevent or delay the occurrence of severe trauma complications,and improve the prognosis of injured patients",and uses C57BL/6 mice as experimental animals to investigate the efficacy and safety of IND and CIP combined in the treatment of mice with severe trauma infection,as well as the effect on macrophage secretion function and its molecular mechanism through in vivo and ex vivo study modes,using experimental zoological,pathological,immunological,genomic,molecular and cell biological techniques.The results showed that,based on the successful construction of a mouse model of severe trauma infection and the determination of the optimal dose and relevant time points of IND and CIP in vivo and in vitro,the combination of IND and CIP could increase the survival rate of model mice,reduce the degree of inflammatory response in model mice,and enhance the in vivo antibacterial effect of model mice,and did not significantly damage the function of important organs such as liver,kidney and heart of model mice,suggesting that the combination of IND and CIP can be effective and safe in treating model mice.IND,together with CIP,can inhibit the secretion function of RAW264.7 cells and mouse peritoneal macrophages,and cause interleukin(IL)-1β,IL-6,IL-10,IL-22,IL-23 A,IL-17 A,IL-17 F and cluster of differentiation(CD)11b.The significant changes in the genes and encoded proteins of CD11 b suggest that macrophages may be important target cells for the inhibition of inflammatory response by the combination of IND and CIP;the intervention of PI3 K inhibitor LY294002 can affect the regulation of the secretory function of the above-mentioned types of macrophages by the combination of the two drugs,and cause Akt at serine This suggests that the regulation of the secretion of inflammatory factors by IND and CIP may be accomplished through the PI3K/Akt signaling pathway,and the important molecular mechanism is the altered phosphorylation level of Akt.This study is part of the "Basic Research" section of the Special Project for Improving Scientific and Technological Innovation Capability of Army Medical University(2019XYY22).It introduces the concept of "new use of old drugs",and for the first time explores the synergistic effects of IND and CIP in the treatment of mice with severe traumatic infections and their effects on inflammation development,infection control and prognosis,clarifies the target cell characteristics of macrophages in the combination of the two drugs,and elucidates the molecular mechanism of PI3K/Akt signaling pathway in the combination of the two drugs.The results of this study are in line with the project’s "Prognosis of Macrophages".The results of this study,combined with the "field research" and "clinical research" parts of the project,will be beneficial to the formation and promotion of the key technology of the combination of NSAIDs with antibiotics to prevent and treat severe trauma infections,promote people’s health maintenance and improve the level of trauma treatment in China.