METHODS: A total of 120 six-month-old Sprague-Dawley (SD) rats were randomized to six groups: Sham, sham + infection (Sham-Inf), sham with infection + antibiotics (Sham-Inf-A), ovariectomized (OVX), OVX + infection (OVX-Inf), and OVX + infection + antibiotics (OVX-Inf-A). Open femoral diaphysis fractures with Kirschner wire fixation were performed. Staphylococcus aureus at 4 × 104 colony-forming units (CFU)/ml was inoculated. Rats were euthanized at four and eight weeks post-surgery. Radiography, micro-CT, haematoxylin-eosin, mechanical testing, immunohistochemistry (IHC), gram staining, agar plating, crystal violet staining, and scanning electron microscopy were performed.
RESULTS: Agar plating analysis revealed a higher bacterial load in bone (p = 0.002), and gram staining showed higher cortical bone colonization (p = 0.039) in OVX-Inf compared to Sham-Inf. OVX-Inf showed significantly increased callus area (p = 0.013), but decreased high-density bone volume (p = 0.023) compared to Sham-Inf. IHC staining showed a significantly increased expression of TNF-α in OVX-Inf compared to OVX (p = 0.049). Significantly reduced bacterial load on bone (p = 0.001), enhanced ultimate load (p = 0.001), and energy to failure were observed in Sham-Inf-A compared to Sham-Inf (p = 0.028), but not in OVX-Inf-A compared to OVX-Inf.
CONCLUSIONS: In osteoporotic bone with FRI, infection was more severe with more bone lysis and higher bacterial load, and fracture-healing was further delayed. Systemic antibiotics significantly reduced bacterial load and enhanced callus quality and strength in normal bone with FRI, but not in osteoporotic bone. Cite this article: Bone Joint Res 2022;11(2):49-60.
方法:将120只6个月大的Sprague-Dawley(SD)大鼠随机分为6组:假,假+感染(Sham-Inf),假感染+抗生素(Sham-Inf-A),卵巢切除(OVX),OVX+感染(OVX-Inf),和OVX+感染+抗生素(OVX-Inf-A)。采用克氏针固定治疗开放性股骨干骨折。接种4×104个菌落形成单位(CFU)/ml的金黄色葡萄球菌。在手术后4周和8周对大鼠实施安乐死。射线照相术,Micro-CT,苏木精-伊红,机械测试,免疫组织化学(IHC),革兰氏染色,琼脂平板,结晶紫染色,和扫描电子显微镜。
结果:琼脂平板分析显示骨骼中的细菌负荷较高(p=0.002),和革兰氏染色显示与Sham-Inf相比,OVX-Inf中更高的皮质骨定植(p=0.039)。OVX-Inf显示出愈伤组织面积显著增加(p=0.013),但与Sham-Inf相比,高密度骨体积减少(p=0.023)。IHC染色显示与OVX相比,OVX-Inf中TNF-α的表达显著增加(p=0.049)。骨骼上的细菌负荷显着减少(p=0.001),增强的极限载荷(p=0.001),与Sham-Inf相比,在Sham-Inf-A中观察到破坏能量(p=0.028),但不在OVX-Inf-A与OVX-Inf相比。
结论:在具有FRI的骨质疏松骨中,随着更多的骨溶解和更高的细菌负荷,感染更严重,骨折愈合进一步延迟。全身抗生素显著降低细菌负荷,增强FRI正常骨的骨痂质量和强度,但不是骨质疏松的骨头。引用这篇文章:骨关节Res2022;11(2):49-60。