血清IL-6水平在小鼠术后早期内植物感染中的筛查作用

The effect of screening test of serum IL-6 for a mouse model of early postoperative implant infection

目的建立小鼠早期内植物感染模型，比较血清白细胞介素-6（IL-6）和C反应蛋白（C-RP）水平，为小鼠内植物感染模型提供一种早期的血清学标志物。方法40只6～8周龄雌性Babl／cdx鼠随机平均分为A、B、C、D四组，将金属内植物逆行植入C、D组小鼠股骨远端，于B、D组右膝关节腔内接种5×105集落形成单位（colony formingunit，CFU）的金黄色葡萄球菌，A、C组注射生理盐水。术后第3天分别测定两组小鼠IL-6和CRP水平。术后第7天分别行X线检查，组织切片HE染色，细菌培养检查，内植物电镜扫描。结果术后第3天，金黄色葡萄球菌对血清IL-6表达的影响有显著影响，但内植物对血清IL-6表达的影响无统计学差异，同时期金黄色葡萄球菌和内植物对血清C．RP表达的影响无统计学差异（P〉0．05）。以细菌培养出金黄色葡萄球菌为诊断感染标准，A、C组术后无感染，B、D组分别有8只、10R小鼠感染。结论本实验成功构建了小鼠早期内植物感染模型。与C．RP相比，血清IL．6水平能更早筛查小鼠术后内植物感染。

Objective A mouse model of early postoperative implant infection was developed to compare the serum level of interleukin-6（IL-6） and C-reactive protein （C-RP）. Methods Forty female adult Balb/c mice were equally divided into A, B, C and D group at random. After locating the femoral trochlear groove, the right femoral intramedullary canal was manually reamed, an aseptic stainless syringe needle was surgically placed in a retrograde fashion into the intramedullary canal of the right femur of group C and D.After the surgical site was closed, an inoculum of 5xl05CFU S. aureus or normal saline alone was pipetted into the joint space in group B and D or group A and C, respectively. Blood samples were collected from all groups on day 3 after the operation,the sera were serially diluted, IL-6 and C-RP were measured.The animals were sacrificed after 7 days, and X-ray, histologic analysis, scanning electron microscope（SEM） and bacterium culture was carried out to detect infection on the joint and on the removed implant. Results None of the mouse was infected in group A or group C, 8 and 10 mice were infected in group B or D, respectively. The two-way ANOVA was adopted to analyse data,main effect of S. aureus on expression of IL-6 on day 3 postoperatively demonstrates a discrepancy on statistics, and implant on expression of IL-6 demonstrates no statistics difference; while main effect of S. aureus and implant on expression of C-RP on day 3 postoperatively demonstrates demonstrate no statistics difference. Conclusions A mouse model of early implant infection can be established successfully 7 days after S. aureus injecting into the joint immediately after surgery. Compared with C-RP, IL-6 measurement provides an excellent sceening test for early postoperative implant infection.