目的 观察早期低频电刺激对兔伸直型膝关节挛缩的治疗作用,并探讨其可能的干预机制.方法 将24只新西兰白兔随机分成对照(C)组、单纯电刺激(E)组、自然恢复(NR)组和电刺激治疗(EST)组,每组6只.C组自由活动7周;E组先自由活动4周,随后对左后肢股四头肌给予3周的低频电刺激;NR组先将左膝关节伸直固定4周,随后解除固定自然恢复3周;EST组先将左膝关节伸直固定4周,随后对左后肢股四头肌给予3周的低频电刺激.每组干预结束后,分别测量兔左膝关节剔除肌肉前后的活动范围(ROM),对股直肌进行HE和Masson染色,Western blot检测股直肌和关节囊中转化生长因子-β1(TGF-β1)和α-平滑肌肌动蛋白(α-SMA)的蛋白表达量.结果 与NR组相比,EST组膝关节的总挛缩和肌源性挛缩减轻(P＜0.01),关节源性挛缩未见改善;股直肌HE染色显示EST组肌纤维的形状和肌膜完整性较NR组改善,Masson染色的定量分析显示EST组股直肌纤维化的改善程度高于NR组(P＜0.01).此外,EST组股直肌中TGF-β1和α-SMA的表达量较NR组减低(P＜0.05),EST组关节囊中TGF-β1和o-SMA的蛋白表达量较NR组关节囊相比差异无统计学意义.结论 早期低频电刺激可通过降低骨骼肌纤维化水平来改善兔膝关节伸直型挛缩;且对骨骼肌纤维化的抑制作用大于对关节囊纤维化的抑制作用.

目的 探讨在兔伸直型膝关节挛缩模型中肌源性挛缩的病理特征及其可能机制.方法 选取新西兰白兔30只,根据固定时间,随机分为以下5组(n = 6):对照组(I-0,不进行任何处理)、固定1周组(I-1,左膝关节伸直位固定1周)、固定2周组(I-2,左膝关节伸直位固定2周)、固定4周组(I-4,左膝关节伸直位固定4周)和固定8周组(I-8,左膝关节伸直位固定8周).然后通过检测固定后膝关节挛缩角度、股直肌Masson染色、低氧诱导因子(HIF)-1α和转化生长因子(TGF)-β1的蛋白表达水平,分析各组结果差异.结果 在固定8周内,固定组的肌源性挛缩角度在4周内随着固定时间的延长而增加,但4周后I-4组和I-8组相比差异无统计学意义.Masson染色结果提示,股直肌横截面积在固定4周内不断降低,而胶原纤维沉积占比在固定4周内不断升高,但固定4周后I-8组与I-4组相比,股直肌横截面积的降低和胶原纤维沉积占比的增加差异均无统计学意义.股直肌HIF-1α蛋白表达水平在固定4周内不断升高,但4周后I-4组和I-8组相比差异无统计学意义;2周内TGF-β1蛋白表达增加差异有统计学意义,2周后每个固定组相比差异无统计学意义.结论 在兔伸直型膝关节挛缩模型中肌源性挛缩的病理特征主要为肌纤维化和萎缩的时间依赖性改变,并且其机制可能与HIF-1α和TGF-β1高表达有关.

OBJECTIVE:The purpose of this study was to examine the intervention effect of radial extracorporeal shock wave combined with ultrashort wave diathermy on immobilization-induced fibrosis and contracture of muscle.DESIGN:The groups included male rabbits for the group (control group). To cause joint contracture, rabbits underwent plaster fixation of a left knee joint at full extension. After immobilization for 4 wks, all rabbits were randomly divided into five groups: model group, natural recovery group, radial extracorporeal shock wave treatment group, ultrashort wave diathermy group, and radial extracorporeal shock wave combined with ultrashort wave diathermy group. All intervention effects were assessed by evaluating the cross-sectional area and the collagen deposition of muscle, the knee joint range of motion and the protein levels for transforming growth factor β1 and hypoxia-inducible factor 1α.RESULTS:The combined treatment group got the best recovery of the knee joint function. The combined treatment was more effective than radial extracorporeal shock wave or ultrashort wave diathermy alone against the fibrosis and contracture of muscle, as well as the overexpression of transforming growth factor β1 and hypoxia-inducible factor 1α.CONCLUSIONS:Radial extracorporeal shock wave combined with ultrashort wave diathermy was effective in alleviating immobilization-induced contracture and fibrosis of muscle, as well as reducing the molecular manifestations of muscle fibrosis.