| Objective:① To extablish a limb skeletal muscle crush injury model② To explore the security of ultrasound microbubble contrast agent in the application of limb skeletal muscle crush injury animal model③ To explore the diagnostic value of quantitative contrast-enhanced ultrasonography features for crush injury in the hind limb muscle of rabbits.④ To explore the microcirculation formation mechanism of contrast-enhanced ultrasonography imaging performance of limb muscle crush injury in microcirculation levelsMethods:① 48 New Zealand white rabbits were randomly divided into 2 groups:the control group (n=6), experimental group (n=42), the lib muscle crush injury model was created by airing a balloon cuff device with a force of 40 kpa, Then detects muscle W/D ratio, creatine kinase, lactate dehydrogenase, blood urea nitrogen, creatinine, malondialdehyde, myeloperoxidase and tissue pathology at different time points after decompression.②36 New Zealand white rabbits were randomly divided into 3 groups, the lib muscle crush injury model was created by airing a balloon cuff device with a force of 40 kpa. Eeach group was divided into two subgroups by injecting or not injecting micro bubbles via ear marginal vein. Then detects muscle wet dry ratio,creatine kinase, lactate dehydrogenase, blood urea nitrogen, creatinine, malondialdehyde myeloperoxidase and tissue pathology at different time points were detected after decompression.③ A total of 120 New Zealand white rabbits were randomized to receive compression on the left hind limb for either 2 h(n=56) or 4 h(n=56) to induce muscle crush injury. Another 8 animals were not injured and served as normal controls. CE ultrasonography parameters such as peak intensity(PI), area under curve(AUC), ascending slop(AS) and descending slop(DS) and creatine kinase, lactate dehydrogenase, malondialdehyde, myeloperoxidase were measured at 0.5 h,2 h,6 h, 24 h,3d,7d,14d after decompression.④ 72 New Zealand white rabbits were randomly divided into two groups, s, the lib muscle crush injury model was created by airing a balloon cuff device with a force of 40 kpa. CE ultrasonography parameters were detected in first group. Living microcirculation parameters were detected in second group to calculate fine blood vessel diameter and blood flow velocityResult:① Three experimental animals died before the end of the experiment, the survival rate was about 94%. Compared with the parameters of control group, the W/D ratio, creatine kinase, lactate dehydrogenase, blood urea nitrogen, creatinine, malondialdehyde and myeloperoxidase value of experimental groups increased significantly after decompression. The value reached their top at 6 and 24 hour time point, then returned to normal level at 14 day time point. Muscle tissue pathology revealed damage performance such as inflammatory cells infiltration and edema, muscle cell cloudy swelling, degeneration and necrosis.②Four animals died before the end of the experiment, both survival rate were about 89%. All experimental animals behaved normally in the process of experiment. Each parameter index and pathological manifestations between the two groups have no significant difference.③Compared with the uninjured muscle, reperfusion of the injured muscles showed early and high enhancement in CE ultrasonography images. The time-intensity curve showed a trend of rapid lift and gradual drop. The PI and AUC values differed significantly among the three groups and were positively correlated with serum and tissue biomarkers. Rabbits of the 4-h compression group showed significantly higher PI and AUC values, and serum and tissue parameters, than the 2-h compression group at each time points. Other biomarker and pathology imaging of expermental groups were also different from control group.④ Compared with the uninjured muscle, reperfusion of the injured muscles showed early and high enhancement in CE ultrasonography images. The time-intensity curve showed a trend of rapid lift and gradual drop. Compared with control group, the fine arteries and veins’diameter of experimental group were wider, the blood flow velocity was slower, especially the fine veins.Conclusions:①The limb skeletal muscle crush injury model is feasible, with good stability and repeatability.② The ultrasound microbubble contrast agent is safe in the application of skeletal muscle detection.③CE ultrasonography can effectively detect muscle crush injury and monitor dynamic changes of the injured muscle in rabbits. PI and AUC are promising diagnostic parameters for this disease. CE ultrasonography might play an important role in the pre-hospital and bedside settings for the diagnosis of muscle crush injury.④ Living microcirculation detection can reflect the change of muscle micro vascular diameter and blood flow velocity, which have a correlation with quantitative ultrasound imaging parameters. |
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