Zhang Li, Bail Hermann, Mittlmeier Thomas, Haas Norbert P, Schaser Klaus-D
Department of Trauma and Reconstructive Surgery, Charité Campus Virchow, Humboldt-University, Berlin, Germany.
J Trauma. 2003 May;54(5):979-85. doi: 10.1097/01.TA.0000025796.74054.5B.
Severe musculoskeletal soft tissue injury sustained after a closed fracture to the extremities significantly influences bone healing and determines the patient's prognosis. The present study was aimed at quantitatively assessing immediate microcirculatory changes in skeletal muscle and periosteum after standardized closed fracture.
Standardized closed fracture of the left tibia in isoflurane-anesthetized Sprague-Dawley rats (n = 14) was induced using a modified weight-drop technique. The left extensor digitorum longus (EDL) muscle (n = 7) and tibial periosteum (n = 7) were surgically exposed for in vivo fluorescence microscopy 15 minutes after fracture. Nonfractured rats (n = 14) served as controls. EDL muscle edema was determined by the ratio of wet to dry weight (EDL water content).
Closed tibial fracture resulted in a significant reduction of functional capillary density, red blood cell velocity, and volumetric blood flow in both EDL muscle and periosteum. Microvascular diameter, leukocyte adherence, and macromolecular leakage were markedly increased, indicating trauma-induced inflammation and endothelial disintegration. EDL muscle edema was found increased significantly after fracture.
This model permits for the first time direct in vivo visualization and quantification of fracture-induced microhemodynamic changes and cellular interactions within the surrounding soft tissue. It demonstrates that even simple fractures lead to profound microcirculatory disturbances in skeletal muscle and periosteum, and also at sites remote from the diaphyseal fracture site. It provides a useful approach for the development of therapeutic strategies to counteract fracture-induced microvascular dysfunction.
四肢闭合性骨折后发生的严重肌肉骨骼软组织损伤会显著影响骨折愈合并决定患者预后。本研究旨在定量评估标准化闭合性骨折后骨骼肌和骨膜的即时微循环变化。
采用改良的重物坠落技术，在异氟烷麻醉的Sprague-Dawley大鼠（n = 14）中诱导左胫骨标准化闭合性骨折。骨折后15分钟，手术暴露左侧趾长伸肌（EDL）肌肉（n = 7）和胫骨骨膜（n = 7），用于体内荧光显微镜检查。未骨折的大鼠（n = 14）作为对照。通过湿重与干重之比（EDL含水量）来确定EDL肌肉水肿情况。
闭合性胫骨骨折导致EDL肌肉和骨膜的功能性毛细血管密度、红细胞速度和容积性血流量显著降低。微血管直径、白细胞黏附以及大分子渗漏明显增加，表明创伤诱导了炎症反应和内皮解体。骨折后发现EDL肌肉水肿显著增加。
该模型首次实现了对骨折诱导的微循环变化以及周围软组织内细胞相互作用的直接体内可视化和定量分析。结果表明，即使是简单骨折也会导致骨骼肌和骨膜出现严重的微循环紊乱，而且在远离骨干骨折部位的区域也是如此。它为开发对抗骨折诱导的微血管功能障碍的治疗策略提供了一种有用的方法。
