| 【Background】As the number of joint replacements and internal fixation operations continue to increase,orthopaedic implant-related infection is a common and catastrophic complica-tion after orthopedic surgery.It is currently considered that the formation of bacterial biofilm on the surface of implant and the bacterial colonization in bone tissue are the main causes of Implant related infection in orthopedic surgery.By modifying the surface of implant with antibacterial coating,it is the focus of current research to kill or inhibit the adhesion of bacteria when it contacts with implant.In the early stage of our research,povidone-iodine was used as the electrolyte to realize the coating of iodine on the surface of titanium implant by electrophoretic deposition,and it demonstrated that the iodine coating was stable and had good antibacterial activity in vitro experiments.Therefore,the rabbit model of metaphyseal bone infection with S.aureus was established,and histopathology,electron microscopy and confocal techniques were used to evaluate the antibacterial activity of the novel iodine-coated implants.【Method】Establishment the rabbit epiphyseal bone infection model of Staphylococcus aureus.Half of 20 titanium keratin needles,8mm in length and 1mm in diameter,were randomly selected and coated with iodine by electrophoretic deposition using povid-one iodine as the electrolyte.20 New Zealand rabbits were randomly numbered and divided into control group and experimental group.After anesthesia、sterilization and towel laying,electric drill was used to drill a single window with a depth of 10 mm on the medial side of the metaphysis of the left tibia.Control group(n = 10): after implanting common titanium Kirschner needles,they were inoculated with 10 ul 1.0×10 6CFU/ml solution;Experimental group(n =10): after implanting iodine-coated titanium Kirschner needles,they were inoculated with 10 ul 1.0×10 6CFU/ml solution.All animals were sealed with bone wax and sutured with silk thread.The observation period was 1 week or when the animal died.It was evaluated and analyzed by general observation,microbial culture,bone histopathology,Kirschner needle surface scanning electron microscope and confocal microscopy.【Result】1、General condition: All animals survived after 1 week.8 animals in the control group had varying degrees of restricted movement of the left lower limb,wound redness,swelling and exudation,and severe pus exudation was seen,all animals in the experimental group and 2 control animals had normal lower limb movement and good wound healing;2 、 Microbial culture: 9 samples in the control group and 1 in the experimental group were positive,and 1 in the control group and 9 in the experimental group were negative,P value < 0.05,the difference was statistically significant;3 、 Bone histopathology: acute osteomyelitis infection was found in 9control groups and 2 experimental groups,but no obvious infection was found in 1control group and 8 experimental groups.And through the Jupiter bone infection pathological score,P value< 0.05,the difference was statistically significant;4 、Scanning electron microscopy : scattered adherence of S.aureus was observed on the surface of the common Kirschner needle in 8 controls,and no bacterial adhesion was observed in the remaining 2 controls and all experimental groups;5 、 Confocal technique: a large amount of green fluorescence was seen in the control group with red fluorescence in spots.,green fluorescence distribution was not clearly observed in the experimental group;6 、 transmission electron microscope: no S.aureus was observed both in the control and the experimental group.【Conclusion】By successfully establishment the rabbit epiphyseal bone infection model of S.aureus,and analyzing the results by microbial culture,bone histopathology,scanning electron microscope and confocal staining,we find that the iodine-coated implants have excellent antibacterial and anti-adhesion properties against S.aureus and have a bright prospect of clin-ical application. |
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