| Objective: To investigate the efficacy of vancomycin(Vm)-loaded microbubbles(MBs)combined withultrasound targeted microbubble distruction(UTMD)in the treatment of periprosthetic joint infection(PJI)caused by methicillin-resistant Staphylococcus aureus(MRSA).-resistant Staphylococcus aureus(MRSA)in the treatment of periprosthetic joint infection(PJI).Methods: 1)Vm-MBs were prepared by thin film hydration method,and the characterization and morphological observation of Vm-MBs were examined using zeta potential analyzer,hemocytometer,high performance liquid chromatography,fluorescence microscope and scanning electron microscope.2)In vitro models of MRSA biofilms were constructed,and the biofilm models were identified using crystalline violet staining,confocal microscope and scanning electron microscope.The MBs were labelled with Dil fluorescent stain and the biofilm with SYTO59 stain,and the MBs were observed in relation to the biofilm position by confocal microscopy.The biofilms were divided into Control group,MBs group,Vm group,Vm-MBs,UTMD group and Vm-MBs+UTMD group.After each group was treated accordingly,the structural changes of biofilms in each group were observed by confocal microscopy and the structural changes of bacterial morphology inside the biofilms were observed by scanning electron microscopy.The change in biofilm density was measured using crystalline violet staining combined with enzyme marker,and the thickness of biofilm and bacterial activity in each group was observed using LIVE/DEAD staining combined with confocal microscopy.3)To construct a rat peri-prosthetic knee infection model and evaluate this model,rats were divided into sham-operated(Sham group),positive control(PJI group),ultrasound-targeted microbubble destruction(UTMD group),vancomycin-loaded microbubble(Vm-MBs group)andultrasound-targeted vancomycin-loaded microbubble(Vm-MBs+UTMD group),and the general and local status of each group was measured preoperatively and postoperatively.Bone destruction around the prosthesis and the position of the prosthesis were observed by X-ray;the prosthesis and peri-prosthetic tissue were taken and assessed for biofilm structure and bacterial activity by scanning electron microscopy and bacterial load testing;the inflammatory response of the body was analysed by taking serum specimens from rats and combining them with histopathology of the knee joint;the bone tissue taken was stained with anti-tartrate acid phosphatase and immunohistochemistry and then assessed for peri-prosthetic bone remodelling by Micro CT.Results: 1)Vm-MBs were constructed to meet the experimental requirements.2)After treatment with Vm-MBs + UTMD,the dense structure of MRSA biofilm was significantly damaged,the biofilm density was significantly decreased,the thickness became thinner and the bacterial activity within the membrane was significantly reduced.3)After treatment with Vm-MBs+UTMD,swelling of the knee joint in rats was significantly reduced,periprosthetic bone destruction was alleviated,biofilm on the surface of the prosthesis was significantly disrupted,bacterial activity of the prosthesis and periprosthetic tissues was significantly reduced,abnormal inflammatory response was corrected,osteoclast and osteoblast levels were balanced,bone metabolism was balanced,and abnormal bone remodelling was corrected.Conclusion: The results of the study showed thatultrasound-targeted vancomycin-loaded microbubbles were applied to PJI in the rat knee joint,and the method was effective in treating it.As this method disrupts the biofilm on the surface of the prosthesis,it also achieves in situ targeted release of vancomycin,which significantly reduces the bacterial activity of the prosthesis and periprosthetic tissue,corrects the abnormal inflammatory response of the body,regulates the level of osteoclasts and osteoblasts,resulting in a balanced bone metabolism,corrects abnormal bone remodelling and avoids periprosthetic bone destruction. |
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