电针干预经TGF-β1/Smad3信号通路对失神经肌萎缩大鼠肌卫星细胞分化的影响

Effects of Electroacupuncture on Differentiation of Muscle Satellite Cells through Controlling TGF-β1/Smad3 Signal Pathway in Denervated Rats

目的:观察电针干预对失神经肌萎缩大鼠腓肠肌中转化生长因子β1(TGF-β1)/Smad3信号通路以及与肌卫星细胞分化密切相关的成肌分化抗原(Myod1)、组蛋白去乙酰化酶4(HDAC4)、微小RNA206(Mir-206)表达的影响,探讨电针延缓失神经肌萎缩发展的可能机制。方法:将24只雄性SD大鼠随机分为假手术组(n=8)、模型组(n=8)和电针组(n=8)。通过横断坐骨神经制备大鼠右后肢失神经肌萎缩模型。造模后对电针组大鼠术侧足三里、环跳穴进行电针干预,每次10 min,每日1次,每周6次,连续4周;假手术组和模型组大鼠不予电针干预。电针干预结束后计算各组大鼠的腓肠肌湿重比、HE染色测定腓肠肌纤维横截面积,实时荧光定量PCR法检测各组大鼠腓肠肌中肌卫星细胞分化相关因子mRNA的相对表达量。结果:4周后,模型组大鼠腓肠肌湿重比、肌纤维横截面积以及术侧腓肠肌中Smad7 mRNA相对表达量均低于假手术组和电针组,差异有统计学意义(P<0.05);模型组术侧腓肠肌中HDAC4、TGF-β1、转化生长因子β受体1(TGF-βr1)、TGF-βr2、Smad3 mRNA相对表达量均高于假手术组和电针组,差异有统计学意义(P<0.05);模型组术侧腓肠肌中Myod1、Mir-206 mRNA相对表达量高于假手术组,但低于电针组,差异有统计学意义(P<0.05)。结论:电针干预可能通过抑制TGF-β1/Smad3信号通路,下调HDAC4mRNA的表达,并上调Myod1、Mir-206 mRNA的表达促进肌卫星细胞的分化,从而延缓大鼠腓肠肌失神经肌萎缩的发展。

Absract Objective To explore the effect of electroacupuncture(EA)on the transforming growth factor-β1(TGF-β1)/Small mother against decapentaplegic(Smad3)signal pathway and the expression of myogenic differentiation antigen(Myod1),histone deacetylase 4(HDAC4),MicroRNA 206(Mir-206)in denervated rats,so as to explore its mechanisms.Methods Twenty-four Sprague-Dawley adult malerats were randomly divided into a sham operation(Sham)group(n=8),a model(M)group(n=8)andan EA treatment(EA)group(n=8).The denervated muscle atrophy model was established by cuttingdown the right sciatic nerve in the EA and M groups.Group EA was applied 10-minute EA to theright Zusanli(ST 36)and Huantiao(GB 30)once a day,six times a week for 4 weeks,while the oth-er two groups were not treated with EA.Then all rats were sacrificed and the ratio of gastrocnemiuswet weight was calculated.The cross-sectional area(CSA)was measured after the hematoxylin and eo-sin staining.The expression levels of satellite cells differentiation associated factors mRNA were detect-ed with quantitative real-time PCR.Results After the 4-week treatment,the ratio of wet weight,the CSA,the relative expression level of Smad7 mRNA in gastrocnemius of group M were significantly lower than the Sham group and EA group(P<0.05).The relative expression of HDAC4,TGF-β1,TGF-βr1,TGF-βr2 and Smad3 mRNA in the affected gastrocnemius of group M were significantly higherthan the other two groups(P<0.05).The relative expression of Myod1 and Mir-206 mRNA in the affected gastrocnemius of group M were significantly higher than the Sham group but significantly lowerthan the EA group(P<0.05).Conclusion The EA treatment may delay the gastrocnemius atrophy in de-nervated rats,which is possibly associated with its effects on down-regulating the TGF-β1/Smad3 sig-nal pathway and the expression of HDAC4 mRNA,and up-regulating the expression of Myod1 and Mir-206 mRNA to promote the differentiation of the satellite cells.