不同强度的低强度脉冲超声波对椎间盘退变的影响

Effects of low-intensity pulsed ultrasound at different intensities on intervertebral disc degeneration in mice

目的 探讨不同强度的低强度脉冲超声波对椎间盘退变的影响,筛选低强度脉冲超声波的最佳治疗强度。方法 采用3种强度（0. 1、0. 5、1. 0 W/cm^2）的低强度脉冲超声波处理大鼠髓核细胞及筛选的最佳强度超声波处理针刺椎间盘模型小鼠; EdU检测髓核细胞增殖,划痕实验检测细胞迁移,定量PCR检测蛋白聚糖、Ⅱ型胶原、波形蛋白等相关基因表达;组织学分析小鼠尾部椎间盘退变程度。结果 3种强度的低强度脉冲超声波能促进髓核细胞增殖及迁移,强度为0. 5 W/cm^2及1. 0 W/cm^2的低强度脉冲超声波作用较明显（P 〈0. 01）。低强度脉冲超声波也可上调正常环境及炎症刺激下髓核细胞中蛋白聚糖、波形蛋白等表达,其中强度为0. 5 W/cm^2、频率为3 MHz、占空比为50%中强度的低强度脉冲超声波作用最强（P 〈0. 01）。对照组小鼠椎间盘表现出明显退变表型,而超声组椎间盘退变程度的组织评分明显低于对照组（P 〈0. 01）。结论 低强度脉冲超声波可能通过上调椎间盘的蛋白聚糖、波形蛋白、Ⅱ型胶原表达,加快细胞增殖及迁移等,对椎间盘退变有一定防治作用,其中强度为0. 5 W/cm^2、频率为3 MHz、占空比为50%中强度的低强度脉冲超声波作用最明显。

Objective To investigate the effect of low-intensity pulsed ultrasound （ LIPUS ） at different intensities on intervertebral disc degeneration （IDD） and determine the optimal therapeutie intensity. Methods LIPUS at the intensities of 0. 1, 0.5 and 1.0 W/cm^2 were applied on rat nucleus pulposus （NP） cells, and the optimal therapeutic intensity LIPUS was performed in a mouse model of intervertebral disc punctures. The cell proliferation and migration were detected by EdU and wound healing assays, respectively, and the expression levels of the related genes were examined using real-time quantitative PCR. Histological analysis was performed to evaluate the degeneration of the intervertebral discs in the mouse model after LIPUS treatment. Results LIPUS treatments at the 3 intensities all promoted the proliferation and migration of rat NP cells, but the effect was stronger with LIPUS intensities of 0. 5 and 1.0 W/cm^2 （P 〈 0.01 ）. The treatments up-regulated the mRNA expression levels of Aggrecan and Vimentin in rat NP cells, and the effect was the most obvious at the intensity of 0.5 W/cm^2（ frequency of 3 MHz with a duty cycle of 50% ; P 〈 0.01 ）. In LIPUS-treated mouse models of disc punctures, histological scoring showed a significantly lower score for IDD than that in untreated mice （ P 〈 0. 01 ）. Conclusion LIPUS can ameliorate IDD by up-regulating the expressions of Aggrecan, Vimentin and type Ⅱ collagen to promote the proliferation and migration of NP cells. An intensity of 0.5 W/cm^2, a frequency of 3 MHz and a duty cycle of 50% can be the optimal LIPUS setting for treatment of IDD.