低强度脉冲超声对兔膝骨关节炎软骨细胞外基质的影响及机制

目的：观察低强度脉冲超声（LIPUS）对兔膝骨关节炎软骨细胞外基质修复的影响并分析其作用机制。方法：选取60只成年雌性家兔,体质量（2.0±0.2）kg,采用随机抽签法分为实验组和对照组,每组30只。采用Hulth法复制膝骨关节炎模型。造模后2周,实验组予以LIPUS治疗,超声工作频率为（800±5%）KHz、最大输出空间平均声功率为（50±10%）mw/cm2,每日1次,每次20 min;对照组予以假LIPUS治疗（即操作与实验组相同,而探头无能量输出）。分别于治疗后第2、4、8周随机处死动物,每次实验组和对照组各10只。观察软骨大体改变、HE染色组织病理改变,采用免疫组化技术和RT-PCR技术分析软骨中的Ⅱ型胶原、蛋白多糖、MMP-3、MMP-7以及MMP-13,采用硝酸还原法分析软骨中的NO的含量。结果：同一时间点的实验组与对照组比较,实验组软骨的损伤程度比对照组轻微（P〈0.01）;实验组软骨中MMP-3、MMP-7、MMP-13和NO的含量均低于对照组（P〈0.01）;实验组软骨中Ⅱ型胶原和蛋白多糖的含量均高于对照组（P〈0.01）。结论：低强度脉冲超声可以通过降低软骨中MMP-3、MMP-7、MMP-13的表达,抑制NO的分泌,促进Ⅱ型胶原和蛋白多糖的合成,来加快损伤软骨的修复。

Effects and mechanism of low-intensity pulsed ultrasound on extracellular matrix in rabbit knee osteoarthritis

Objective：To observe the effects of low intensity pulsed ultrasound （LIPUS） on repairing extracellular matrix in rabbit knee osteoarthritis and analyze its mechanism. Methods：Sixty adult female rabbits with an average weight of （2.0± 0.2） kg,were divided randomly into two groups （experimental group and control group,30 rabbits in each group）. All rabbits were replicated in right knees by Hulth method for knee osteoarthritis model. Two weeks after operation ,the rabbits in experimental group were treated with LIPUS,and the ultrasonic frequency was （800±5%）KHz and the maximum intensities of spatially averaged and time averaged（SATA） was （50±10%） mw/cm2,for 1 time a day and every time 20 min,while the rabbits in control group were treated with sham LIPUS ,the same operation with experimental group but without energy output. At the 2,4,8 weeks after treatment,10 rabbits in each group were randomly killed for each time. The general changes of cartilage and its histopathological changes by HE staining were observed;the expression of collagen typeⅡ,proteoglycan,MMP-3,7,13 in cartilage were analyzed by immunohistochemical and RT-PCR technique;and the expression of NO in cartilage was analyzed by nitrate reduction method. Results：On the same observed time point,the damage degree of cartilage in experimental group was slighter than that of control group（P〈0.01）,the expression of MMP-3,7,13 and NO in cartilage in experimental group was lower than that of control group （P〈0.01） while collagen typeⅡand proteoglycan was higher than that of control group （P〈0.01）. Conclusion：Low intensity pulsed ultrasound can repair the damaged cartilage by reducing the expression of MMP-3,7,13,inhibiting the secretion of NO and promoting the synthesis of collagen typeⅡand proteoglycan in cartilage.