低强度脉冲式超声对实验性兔骨关节炎软骨损伤修复的影响

Effect of low intensity pulsed ultrasound in repairing rabbits cartilage injury caused by experimental osteoarthritis

目的研究低强度脉冲式超声(LIPUS)对实验性兔骨关节炎软骨损伤修复的影响及其作用机制。方法取36只成年新西兰兔,双膝关节经改良Hulth法建立骨关节炎模型,右膝为LIPUS组,左膝为对照组。2周后LIPUS组接受LIPUS治疗,超声强度30mW/cm^2,频率1.0 MHz,频宽200μs,重复频率1.0KHz,每日一次,每次15 min;对照组接受假超声治疗(过程同LIPUS组,但超声治疗仪不开机,探头无能量输出)。分别于治疗后2周、4周、8周处死实验动物,每批12只,观察软骨大体改变并行组织病理学(HE染色、Ⅱ型胶原免疫组化、MMP-13免疫组化)检测,结果采用统计学分析。结果在相同观察时间点的软骨损伤程度,LIPUS治疗组比对照组轻微,LIPUS治疗组Ⅱ型胶原表达强度高于对照组,MMP-13表达强度低于对照组,差异均有统计学意义。结论LIPUS能促进骨关节炎软骨Ⅱ型胶原的合成,并能通过降低MMP-13的表达,减少细胞外基质的降解,从而促进骨关节炎软骨损伤的修复。

Objective To investigate the effect and underlying mechanisms of low intensity pulsed ultrasound （LIPUS） in repairing rabbits cartilage injury caused by experimental osteoarthritis. Methods Experimental osteoarthritis were replicated in both knees of thirty-six mature New Zealand rabbits by modified Hulth＇s modeling method. They were divided into two groups, the right knees were LIPUS group and the left knees were control group. Two weeks after operation the right knees were given LIPUS therapy, of which the intensity was 30 mW/cm^2 , the frequency was 1.0 MHz with a 200-microsecond tone burst and the repeated frequency was 1.0 kHz. The LIPUS therapy was administered once a day and lasted for 15 min every time. For the control group, the left knees were given sham US therapy （the procedure was the .same as LIPUS group, but uhrasonic machine was off and no energy was exported from the detecting head）. The experimental animals were randomly sacrificed at 2 weeks, 4 weeks and 8 weeks after therapy and 12 rabbits were sacrifieed for each time. The articular cartilages were obtained and observed by unaided eye and microscope, then histopatbology microscopy （HE, typeⅡ collagen immunohistochemistry stain, MMP-13 immunohistochemistry stain） were done and the results were analyzed statistically. Results On the same ohaerved time point, the joint cartilage injury of the LIPUS group was slighter than that of the control group, the type Ⅱ collagen expression in the LIPUS group was higher than in the control group, the MMP-13 expression was lower in the LIPUS group than in the control group, all the differences between the two groups had statistical significance. Conclusions LIPUS can promote the repair of the osteoarthritis cartilage injury through increasing type Ⅱ collagen synthesis and decreasing the expression of MMP13 to decrease the degeneration of extraeellular matrix.