超声波促进大鼠骨骼肌挫伤修复的生物力学研究

目的：从生物力学角度探讨脉冲超声波对促进大鼠骨骼肌挫伤修复的作用。方法：成年雄性SD大鼠30只，将其中24只作为实验组，制作成双侧腓肠肌挫伤模型，损伤24h后，对大鼠左后肢使用频率3Hz，强度0.25W／cm^2，50％循环的脉冲超声波治疗，每日1次，持续5min；右后肢行假治疗。另6只作为空白对照组。分别于损伤后14、21、28及35d时取材进行生物力学指标测试。结果：治疗28d时，实验组大鼠左后肢最大载荷及屈服强度已恢复至正常水平，与对照组比较差异无统计学意义；左后肢35d的肌肉湿重和抗拉强度也与对照组差异无统计学意义。右后肢35d时各项指标仍明显低于对照组（P〈0.01）。结论：超声波治疗可促进骨骼肌挫伤的愈合，并能显著提高其愈合质量。

The Biomechanical Research of Pulsed Ultrasound for Repair of Rat Skeletal Muscle Contusion

Objective：To biomechanically investigate the pulsed ultrasound therapy for repair of rat skeletal muscle contusion. Methods：Of 30 3-month-old adult male SD rats, 24 received a bilateral contusion injury to the gastrocnemius via a drop mass technique as experimental group, and the remaining 6 rats served as controls. Pulsed ultrasound treatment （frequency, 3 MHz; intensity, 0.25 W/cm^2 ; 50% duty cycle） was given 24 h post-injury, 5 min, once every day on the left hindlimb, and the contralateral right hindlimb was subjected to dummy treatment. At the day 14, 21, 28, and 35 after injury, the biomechanical performance of the injured gastroenemius was tested. Results：In this experiment, there was an increase in biomechanical properties after ultrasound treatment. At the day 28 after injury, the limit load and yield strength were restored to the normal levels, and at the day 35 after injury, there was no significant difference in wet weight and tensile strength between experimental group and control group. At the day 35 after injury, the limit load, yield strength, wet weight and tensile strength were significantly decreased as compared with control group （P〈0.01）. Conclusion：The pulsed ultrasound therapy can promote the healing of the skeletal muscle contusion and prominently improve the quality of injured skeletal muscle.