电刺激对兔膝关节挛缩的治疗作用及其抗纤维化机制研究

Study on the therapeutic effect of electrical stimulation on the knee joint contracture and its anti-fibrosis mechanism in rabbits

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α-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。

Objective To explore the therapeutic effect of early low-frequency electrical stimulation on knee extension contracture and its possible intervention mechanism in rabbits.Methods Twenty-four New Zealand white rabbits were randomly divided into control group(C),electrical stimulation group(E),natural recovery group(NR)and electrical stimulation treatment group(EST),with 6 rabbits in each group.Group C had free activity for 7 weeks.In group E,free activity was performed for 4 weeks,followed by low frequency electrical stimulation on the quadriceps of the left hind limb for 3 weeks.In group NR,the left knee joint was fixed in the straight position for 4 weeks,and then 3 weeks of free activity was given after the fixed removing.In the EST group,the left knee joint was fixed in the straight position for 4 weeks,followed by low frequency electrical stimulation on the quadriceps of left hind limb for 3 weeks.After each group intervention,the range of motion(ROM)of the left knee joint was measured before and after muscle removal.HE staining and Masson staining were performed on the rectus femurs.The protein expression levels of transforming growth factor-β1(TGF-β1)andα-smooth muscle actin(α-SMA)in rectus and capsule were detected by Western blot.Results Compared with NR group,total contracture and myogenic contracture of the knee joint were reduced(P<0.01)and arthrogenic contracture was not improved in EST group.HE staining of rectus femoris showed that the shape and membrane integrity of muscle fibers in the EST group were improved compared with those of the NR group.The quantitative analysis of masson staining showed that the fibrosis improvement degree of rectus femoris in the EST group was higher than that of the NR group(P<0.01).In addition,the expression levels of TGF-β1 andα-SMA in the rectus femurs of EST group were lower than those in the NR group(P<0.05).The expression differences of TGF-β1 andα-SMA in joint capsule of the EST group were not statistically significant compared with those in the NR group(P>0.05).Conclusion Early low-frequency electrical stimulation can improve extension contracture of the knee via reducing the level of skeletal muscle fibrosis.The inhibition of skeletal muscle fibrosis is greater than that of joint capsule fibrosis.