| BackgroundAcute osteomyelitis is a common orthopedic disease in clinical work.The pathogenic bacterial is usually Staphylococcus aureus[1,2],which usually occurs after medical device implantation.Even if strict aseptic procedures are performed during surgery and systemic prophylactic antibiotic treatment,acute osteomyelitis still occurs,and it is also an important factor for teratogenic disability.In order to treat infections caused by bacterial,the application of systemic antibiotic treatment by oral and injection is the current clinical standard strategy.The drawback of this treatment is that it is difficult to achieve effective antibacterial concentration in the blood[3].In addition,studies have shown that,in the presence of internal plants,a critical number of contaminated microorganisms smaller than normal will form an infection[4].Therefore,directly addressing infection-related issues from the perspective of the inner plant material itself can effectively reduce the risk of bacterial infections and antibiotic side effects.In recent years,some researchers have developed copper-rich antibacterial stainless steel by adding an appropriate amount of copper to medical metal materials[5].Copper has a strong antibacterial function.Such materials will continuously and tracely release copper ions after being implanted in the body.Thus it has a significant antibacterial effect[6].Previous studies have shown that copper-rich antibacterial stainless steel has a strong inhibitory effect on Staphylococcus aureus and kills Staphylococcus aureus in vitro and in animals[7],but the specific mechanism is not clear-except for the copper ion itself,it has sterilization The mechanism of how copper ions in the microenvironment of the body interact with the organism in the body to kill bacterial and enhance partial resistance is not clear[8].According to the literature report and the research results of this subject,we have confirmed that copper-rich antibacterial stainless steel can promote macrophage proliferation and promote inflammatory phenotype activation of macrophages in animal models of acute osteomyelitis,thereby promoting inhibition and killing of Staphylococcus aureus,thereby reducing the degree of partial infection in the body,and has an effect on improving disease outcome and prognosis of animal models of acute osteomyelitis.Methods1.Establish an animal model of acute osteomyelitis caused by Staphylococcus aureus infection with implants,which are 316L stainless steel metal materials and 316L-Cu copper-rich stainless steel metal materials provided by Professor Ke Yang,Institute of Metal Research,Chinese Academy of Sciences.Bacterial plating,Micro-CT scanning analysis,immunohistochemist ry staining,immunofluorescence staining,and HE staining were used to compare the differences in the degree of bone infection and bacterial loading between the two groups of mice.2.On the basis of animal models,RNA from bone marrow cells and adjacent lymph node cells at the modeling site was extracted,and the levels of inflammatory factors secreted in the two animal models were compared by reverse transcription and quantitative RT-PCR.3.The types and proportions of immune cells in the bone marrow cavity of animal models were analyzed by flow cytometry,and the differences between the two groups were compared.4.The macrophages in the bone marrow cavity of two groups were sorted by flow cytometry,and their RNA was extracted.The levels of macrophage inflammatory factors secreted by the two groups were compared by reverse transcription and quantitative RT-PCR.5.Use 316L stainless steel and 316L-Cu copper-rich stainless steel to cultivate RAW264.7 cells,and compare the effects of the two groups on the proliferation of macrophages.Results1.In an animal model of acute osteomyelitis with implants,316L-Cu copper-rich stainless steel can significantly reduce the bacterial loading in the area of bone infection and reduce partial osteolysis.2.In the 316L-Cu copper-rich stainless steel group,bone marrow cells secrete a large amount of IL-4,IL-6,IL-8,and IL-12,and adjacent lymph node cells secrete a large amount of IL-4,IL-6,and IL-10.These inflammations factors play a role in promoting partial inflammation and killing pathogenic microorganisms,and also promote partial immunity3.In partial immune microenvironment(bone marrow cavity)of the 316L-Cu copper-rich stainless steel group,the number of macrophages increased,and the activation rate was higher.The copper-rich environment could induce macrophages to develop a strong inflammation type changes,inhibit and kill bacterial.4.316L-Cu copper-rich stainless steel material promotes the secretion of inflammatory factors such as IL-6,IL-10,and TNF-α by macrophages in the bone marrow cavity.It has anti-pathogenic microorganisms effect and promotes repair and reconstruction of damaged tissues.5.The copper-rich microenvironment is conducive to the proliferation of macrophages,the partial inhibition and killing of bacterial,and is beneficial to reducing the degree of infection in bone.Conclusion1.In an animal model of acute osteomyelitis with implants,316L-Cu copper-rich stainless steel can significantly reduce the bacterial loading and partial osteolysis in the area of bone infection.Copper ions play a role in inhibiting and killing Staphylococcus aureus.2.In partial immune microenvironment(bone marrow cavity)of the 316L-Cu copper-rich stainless steel group,the number of macrophages increased and the activation type was higher.In the animal model of acute osteomyelitis,the copper-rich environment plays a role in inducing macrophages to undergo a stronger inflammatory phenotype change.3.The copper-rich microenvironment is conducive to the proliferation of macrophages in the bone marrow cavity,which in turn is conducive to the inhibition and killing of bacterial,and is conducive to reducing the degree of infection in bone infection areas. |
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