低强度脉冲超声波对大鼠失神经骨骼肌萎缩的影响

The effect of low intensity pulsed ultrasound on denervated skeletal muscle atrophy in a rat model

[目的]探讨低强度脉冲超声波(LIPUS)对失神经骨骼肌萎缩的影响。[方法]50只健康雄性SD大鼠随机分为五组:假手术组、模型组、60 m W/cm2、110 m W/cm2、170 m W/cm2LIPUS治疗组(即A、B、C、D、E组),n=10。右股后外侧纵向切口暴露并切断坐骨神经造成失神经动物模型,A组不切断神经。术后1 d,C、D、E组术侧腓肠肌分别给予相应强度LIPUS治疗(A、B组不行任何治疗)。术后4周和8周,测定术侧腓肠肌湿重比和肌纤维直径、截面积,Western Blot检测Caspase-3、Caspase-8、Caspase-9表达,TUNEL法检测细胞凋亡,透射电镜观察腓肠肌超微结构。[结果]术侧腓肠肌湿重比和肌纤维直径、截面积,B组明显低于C、D、E组,差异有统计学意义(P<0.05)。Caspase-3、Caspase-8、Caspase-9蛋白表达及细胞凋亡指数,C、D、E组明显低于B组(P<0.05)。透射电镜显示,C、D、E组肌丝溶解、Z线断裂和线粒体肿胀、空泡化均轻于B组。[结论]LIPUS可延缓失神经骨骼肌萎缩进程,其机制可能与调控凋亡相关蛋白表达、减少细胞凋亡有关。

[ Objective] To investigate the effect of low intensity pulsed ultrasound （LIPUS） on denervated skeletal muscle atrophy. [ Methods ] Fifty healthy male SD rats were randomly divided into five groups： sham operation group, model group, 60 mW/cm2 , 110 mW/cm2, 170 mW/cm2 LIPUS treatment groups （groups A, B, C, D, E） , n = 10 in each. The sciatic nerve of rats were exposed and transected through right femoral lateral incision to establish the denervation animal model, the sci- atic nerves in group A were exposed with the same method but not transected. One day after operation, the corresponding intensity LIPUS was applied to the right side gastrocnemius of groups C, D, E, while groups A and B received no treatment. At 4 weeks and 8 weeks after operation, the muscle wet weight ratio , muscle fiber diameter and cross - sectional area of the gastrocnemius were measured, the expression of Caspase - 3, Caspase - 8, caspase - 9 was detected by Western Blot, the apoptosis was detec- ted by TUNEL, the ultrastructure of gastrocnemius was observed with transmission electron microscope. [ Results ] The wet weight ratio and fiber diameter and cross - sectional area were significantly lower in group B than those in groups C, D and E （ P 〈 0. 05 ） . The expression of Caspase - 3 , Caspase - 8 and Caspase - 9 and the apoptosis index in groups C, D, E were significantly lower than those in group B （ P 〈 0.05 ） . Transmission electron microscopy showed that myofilament dissolving, Z line broking, mitochondrial swelling and vacuolization in groups C, D, E were milder than those in group B. [ Conclusion ] LIPUS can retard the process of denervated skeletal muscle atrophy, and its mechanism may be related to the regulating of the expression of apoptosis related proteins and reducing of the cell apoptosis.