目的 探討循環(huán)血miR-345-3p在長骨感染性骨不連中的表達(dá)變化，評估其作為潛在的新型生物標(biāo)志物在長骨感染性骨不連的診斷價值。方法 建立股骨感染性骨不連及開放性截骨大鼠模型，術(shù)后42 d后，拍攝X線評估內(nèi)固定位置及骨折愈合情況；離斷股骨后行micro-CT，檢測骨痂礦物質(zhì)密度（BMD）、骨痂體積/總體積（BV/TV）、骨小梁厚度（Tb.Th）、骨小梁數(shù)量（Tb.N）、骨小梁間隙（Tb.Sp）。使用Sysmex XN-350全血細(xì)胞分析儀進(jìn)行白細(xì)胞計(jì)數(shù)（WBC）；采用免疫散射比濁法測定血中C反應(yīng)蛋白（CRP）表達(dá)水平；采用毛細(xì)管動態(tài)光度計(jì)成像測定法檢測紅細(xì)胞沉降速率（ESR）水平。通過實(shí)時熒光定量PCR（qRT-PCR）檢測和比較感染性骨不連組及骨折組全血中miR-345-3p的表達(dá)水平，并通過受試者工作特征（ROC）曲線評估WBC、CRP、ESR及miR-345-3p在感染性骨不連中的診斷效能。結(jié)果 行X線及micro-CT評估骨折愈合情況，骨折組骨折線模糊，斷端連續(xù)，有連續(xù)骨痂通過骨折線；長骨感染性骨不連組骨折端硬化，斷端有間隙，骨痂間無小梁通過，骨膜增厚。感染性骨不連組術(shù)后42 d，BMD、Tb.Th、Tb.N顯著高于骨折組，Tb.Sp顯著低于骨折組（P<0.05、0.01）。感染性骨不連組WBC、CRP、ESR較骨折組顯著升高（P<0.05），miR-345-3p表達(dá)較骨折組顯著降低（P<0.01）。miR-345-3p診斷的AUC為0.906，優(yōu)于WBC、CRP、ESR。結(jié)論 全血miR-345-3p在長骨感染性骨不連中表達(dá)水平顯著降低，有望成為感染性骨不連診斷的潛在新型生物標(biāo)志物。

Objective To investigate the expression changes of miR-345-3p in circulating blood and evaluate its diagnostic value as a potential new biomarker in infected nonunion of the long bones. Methods The rat models of femoral infected nonunion and open fracture were established. After 42 days of operation, X-ray was taken to evaluate the position of internal fixation and fracture healing; micro CT was performed to detect the bone mineral density (BMD), bone volume/total volume (BV/TV), trabecular thickness (Tb. Th), trabecular number (Tb. N) and trabecular separation (Tb. Sp) of callus. White blood cell count (WBC) was measured by Sysmex XN-350 whole blood cell analyzer, C-reactive protein (CRP) expression was measured by immunonephelometry, erythrocyte sedimentation rate (ESR) was measured by capillary dynamic photometer. Quantitative real time reverse transcription polymerase chain reaction (qRT-PCR) was used to detect and compare the expression level of miR-345-3p in the whole blood of the infected nonunion group and the fracture group. The diagnostic efficacy of WBC, CRP, ESR, and miR-345-3p in infected nonunion were evaluated by the receiver operating characteristic (ROC) curve. Results X-ray and micro CT were used to evaluate the fracture healing. In the fracture group, the fracture line was fuzzy, the fracture end was continuous, and there was a continuous callus passing through the fracture line. In the long bone infectious nonunion group, the fracture end was sclerotic, the fracture end had a gap, there was no trabecula passing through between the callus, and the periosteum was thickened. 42 days after operation, BMD, Tb.Th and Tb.N were significantly higher and Tb.Sp was significantly lower in infected nonunion group than in fracture group (P<0.05, 0.01). WBC, CRP and ESR were significantly higher and miR-345-3p expression was significantly lower in infected nonunion group than in fracture group (P<0.05, 0.01). The AUC of miR-345-3p was 0.906, which was better than WBC, CRP and ESR. Conclusion The expression level of miR-345-3p in infected nonunion of the long bones was reduced, which may be a potential new biomarker for the diagnosis of infected nonunion.

R965

國家自然科學(xué)基金資助項(xiàng)目（81603092）；江蘇省衛(wèi)計(jì)委"科教強(qiáng)衛(wèi)工程"青年醫(yī)學(xué)人才項(xiàng)目（QNRC2016606）