| Objective To observe the effects of electroacupuncture on the motor function and skeletal muscle mitochondrial dynamics of SAMP8 mice,and to explore the mechanism of electroacupuncture in improving the motor dysfunction of Alzheimer’s disease(AD)from the perspective of mitochondrial dynamics,so as to provide a theoretical basis for the treatment of AD motor dysfunction by electroacupuncture.MethodsEighteen 8-month-old male SAMP8 mice were divided into model group and electroacupuncture group according to random number table method.Nine male SAMR1 mice of the same age were selected as the control group.Every afternoon from 15:00 p.m.to17:00 p.m.,the same person covered the mice in the electroacupuncture group with a self-made net and fixed them on the self-made fixator for acupuncture intervention.Points selected Baihui(DU20),Dazhui(DU14)and bilateral Shenshu(BL23),wherein Dazhui point and Shenshu point(bilateral alternate day)connected with the electroacupuncture therapy instrument.The parameters of the electroacupuncture therapy instrument are continuous wave,frequency 2 Hz and current intensity 1.5～2 m A.Electroacupuncture was performed once a day,each time for 20 minutes,and every 8 days was a course of treatment.The interval between each course of treatment was 2 days.There were 3 courses of treatment in total.At the same time every day,the model group and the control group were captured by the same person in the same way and fixed for the same time,but without any intervention.After electroacupuncture treatment,the mice in each group were tested by gripping test,suspension test,hind limb extension test and swimming test.After the test,the samples were collected uniformly.The exercise ability of mice was detected by behavioral methods.The morphology and structure of gastrocnemius in mice were observed by HE staining.The content of ATP in the gastrocnemius of mice was detected by colorimetric method.The relative m RNA expression levels of OPA1,MFN2 and DRP1 in the gastrocnemius of mice were detected by q PCR.The relative expression levels of mitochondrial dynamics related proteins OPA1,MFN2 and DRP1 were detected by Western blot.Results1.The effect of electroacupuncture on the motor function of SAMP8 mice: The grip test results showed that the grip of model group was significantly decreased compared with the control group(P<0.01);Compared with model group,the grip strength of electroacupuncture group was significantly improved(P<0.01).The suspension test results showed that compared with the control group,the suspension test scores of the model group decreased significantly(P<0.01);Compared with the model group,the electroacupuncture group significantly improved the suspension test score(P<0.01).The results of hindlimb extension experiment showed that compared with the control group,the score of hindlimb extension experiment in the model group showed a downward trend;Compared with the model group,the posterior limb extension test scores of the electroacupuncture group showed an increasing trend,but the differences were not statistically significant.The swimming experiment results showed that compared with the control group,the average speed and the maximum speed of the model group decreased significantly(P<0.01);Compared with the model group,the average velocity and the maximum velocity of the electroacupuncture group were significantly increased(P<0.01).2.The effect of electroacupuncture on skeletal muscle morphology and structure of SAMP8mice: HE staining showed that the gastrocnemius fibers of mice in the control group were arranged neatly,the cytoplasm staining was consistent as a whole,and the nuclei were evenly distributed.Compared with the control group,the gastrocnemius fibers in the model group were disordered and had poor continuity,with wider gaps,different staining depth of cytoplasm,and uneven distribution of nuclei.Compared with the model group,the gastrocnemius in the electroacupuncture group was arranged neatly,the space was narrowed,the cytoplasm staining was consistent,and the nucleus distribution was uniform.3.The effect of electroacupuncture on ATP content in the skeletal muscle of SAMP8 mice:The results of ATP content determination showed that compared with the control group,ATP content in the gastrocnemius muscle of mice in the model group was significantly decreased(P<0.01);Compared with model group,ATP content in gastrocnemius muscle of mice in electroacupuncture group was significantly increased(P<0.01).4.The effect of electroacupuncture on skeletal muscle mitochondrial dynamics in SAMP8mice:Quantitative PCR results showed that compared with the control group,the relative expression levels of OPA1 and MFN2 m RNA in gastrocnemius of mice in the model group were significantly decreased(P<0.01),and the relative expression level of DRP1 m RNA in gastrocnemius of mice in model group was significantly increased(P<0.01);Compared with model group,the relative expression levels of OPA1 and MFN2 m RNA in gastrocnemius of mice in electroacupuncture group were significantly increased(P<0.01),and the relative expression level of DRP1 m RNA in gastrocnemius of mice in electroacupuncture group was significantly decreased(P<0.01).Western blot results showed that compared with the control group,the relative expression levels of OPA1 and MFN2 in gastrocnemius of mice in the model group were significantly decreased(P<0.01),and the relative expression level of DRP1 protein in gastrocnemius in the model group was significantly increased(P<0.01);Compared with model group,the relative expression levels of OPA1 and MFN2 in gastrocnemius of mice in electroacupuncture group were significantly increased(P<0.05,P<0.01),and the relative expression of DRP1 protein in gastrocnemius muscle of mice in electroacupuncture group was significantly decreased(P<0.01).ConclusionsBy correcting the skeletal muscle mitochondrial dynamic imbalance of SAMP8 mice,electroacupuncture can improve the skeletal muscle ATP content and energy metabolism of SAMP8 mice,so as to improve the skeletal muscle structure and the motor dysfunction of SAMP8 mice. |
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