Objective To investigate the effects of electroacupuncture for the restoration of muscle regeneration and the secretion of exosomes around acupoints in a model of erector spinae muscle injury.Methods Forty SPF-grade male SD rats were randomly divided into blank group,model group,electroacupuncture group,and electroacupuncture+exosome inhibitor group,with 10 rats per group.Except for the blank group,the erector spinae muscle injury models were established in other groups by intramuscular injection of 0.5%bupivacaine.The blank control group received no treatment,whereas the rats in the electroacupuncture and electroacupuncture+exosome inhibitor groups were treated with electroacupuncture at"Weizhong"(BL40)and"Shenshu"(BL23)acupoints,respectively,stimulation was applied daily for 7 consecutive days,with each session lasting 20 minutes.The parameters used were a sparse-dense wave waveform,a frequency of 2/10 Hz,and a current intensity of 1 mA.The exosome inhibitor GW4869(3 g/L,50 μL per acupoint)was injected 1 h before each electroacupuncture in the electroacupuncture+exosome inhibitor group.After intervention,the erector spinae muscles were collected and observed by HE and Masson staining for morphological changes.The expression of paired box gene 7(Pax7)and recombinant myogenic differentiation(MyoD)was detected by immunohistochemistry,while the expression of myogenin(MyoG)and myosin heavy chain(MyHC)proteins was detected by western blotting.The serum exosomes of rats in each group were extracted and identified by transmission electron microscopy and nanoparticle tracking analysis,and the expression of Alix,differentiation cluster 63(CD63),and tumor susceptibility gene 101(TSG101)proteins were detected by Western blotting.Results Compared with the blank group,the model group,the electroacupuncture group,and the electroacupuncture+exosome inhibitor group exhibited spinae muscle fiber fragmentation,degeneration,necrosis,and inflammatory cell infiltration in HE staining.The result of Masson staining showed that collagen fiber hyperplasia was increased.The model group showed increased expression of MyoD,Pax7,MyoG,MyHC,and CD63,while TSG101 expression was downregulated(P<0.05).In the electroacupuncture group,the expression of MyoD,Pax7,Alix,and TSG101 was elevated(P<0.05),and the expression of MyHC and CD63 was decreased(P<0.05).The electroacupuncture+exosome inhibitor group displayed increased expression of MyHC,Alix,and TSG101(P<0.05),and the expression of CD63 was decreased(P<0.05).Compared with the model group,the electroacupuncture group and the electroacupuncture+exosome inhibitor group showed reduced muscle fiber degeneration,necrotic areas,and inflammatory cell infiltration as observed in HE staining,along with decreased collagen fiber hyperplasia in Masson staining.Specifically,the electroacupuncture group demonstrated increased expression of MyoD,Pax7,MyoG,Alix,and TSG101(P<0.05),and the expression of CD63 was decreased(P<0.05).The electroacupuncture+exosome inhibitor group displayed downregulated expression of Pax7,MyoG,MyHC,and CD63(P<0.05),and the expression of Alix and TSG101 was regulated(P<0.05).Compared with the electroacupuncture+exosome inhibitor group,the electroacupuncture group exhibited less muscle fiber degeneration and necrosis,reduced inflammatory cell infiltration in HE staining,and decreased stained collagen fibers in Masson staining.The electroacupuncture group showed increased expression of MyoD,Pax7,MyoG,MyHC,Alix,and CD63(P<0.05).Conclusion Electroacupuncture can up-regulate the expression of Pax7 and MyoD,and promote the regeneration of erector spinae muscles,which may be related to stimulating the secretion of exosomes around the acupoint.Exosomes may be an important mediator for the efficacy of acupuncture.

Objective To investigate the effects of electroacupuncture for the restoration of muscle regeneration and the secretion of exosomes around acupoints in a model of erector spinae muscle injury.Methods Forty SPF-grade male SD rats were randomly divided into blank group,model group,electroacupuncture group,and electroacupuncture+exosome inhibitor group,with 10 rats per group.Except for the blank group,the erector spinae muscle injury models were established in other groups by intramuscular injection of 0.5%bupivacaine.The blank control group received no treatment,whereas the rats in the electroacupuncture and electroacupuncture+exosome inhibitor groups were treated with electroacupuncture at"Weizhong"(BL40)and"Shenshu"(BL23)acupoints,respectively,stimulation was applied daily for 7 consecutive days,with each session lasting 20 minutes.The parameters used were a sparse-dense wave waveform,a frequency of 2/10 Hz,and a current intensity of 1 mA.The exosome inhibitor GW4869(3 g/L,50 μL per acupoint)was injected 1 h before each electroacupuncture in the electroacupuncture+exosome inhibitor group.After intervention,the erector spinae muscles were collected and observed by HE and Masson staining for morphological changes.The expression of paired box gene 7(Pax7)and recombinant myogenic differentiation(MyoD)was detected by immunohistochemistry,while the expression of myogenin(MyoG)and myosin heavy chain(MyHC)proteins was detected by western blotting.The serum exosomes of rats in each group were extracted and identified by transmission electron microscopy and nanoparticle tracking analysis,and the expression of Alix,differentiation cluster 63(CD63),and tumor susceptibility gene 101(TSG101)proteins were detected by Western blotting.Results Compared with the blank group,the model group,the electroacupuncture group,and the electroacupuncture+exosome inhibitor group exhibited spinae muscle fiber fragmentation,degeneration,necrosis,and inflammatory cell infiltration in HE staining.The result of Masson staining showed that collagen fiber hyperplasia was increased.The model group showed increased expression of MyoD,Pax7,MyoG,MyHC,and CD63,while TSG101 expression was downregulated(P<0.05).In the electroacupuncture group,the expression of MyoD,Pax7,Alix,and TSG101 was elevated(P<0.05),and the expression of MyHC and CD63 was decreased(P<0.05).The electroacupuncture+exosome inhibitor group displayed increased expression of MyHC,Alix,and TSG101(P<0.05),and the expression of CD63 was decreased(P<0.05).Compared with the model group,the electroacupuncture group and the electroacupuncture+exosome inhibitor group showed reduced muscle fiber degeneration,necrotic areas,and inflammatory cell infiltration as observed in HE staining,along with decreased collagen fiber hyperplasia in Masson staining.Specifically,the electroacupuncture group demonstrated increased expression of MyoD,Pax7,MyoG,Alix,and TSG101(P<0.05),and the expression of CD63 was decreased(P<0.05).The electroacupuncture+exosome inhibitor group displayed downregulated expression of Pax7,MyoG,MyHC,and CD63(P<0.05),and the expression of Alix and TSG101 was regulated(P<0.05).Compared with the electroacupuncture+exosome inhibitor group,the electroacupuncture group exhibited less muscle fiber degeneration and necrosis,reduced inflammatory cell infiltration in HE staining,and decreased stained collagen fibers in Masson staining.The electroacupuncture group showed increased expression of MyoD,Pax7,MyoG,MyHC,Alix,and CD63(P<0.05).Conclusion Electroacupuncture can up-regulate the expression of Pax7 and MyoD,and promote the regeneration of erector spinae muscles,which may be related to stimulating the secretion of exosomes around the acupoint.Exosomes may be an important mediator for the efficacy of acupuncture.