Acupuncture is effective for the alleviation of denervated skeletal muscle atrophy. Researchers at the Fujian Provincial Research Institution of Traditional Chinese Medicine conclude that acupuncture reduces myocyte (muscle cell) apoptosis while promoting the proliferation and differentiation of muscle satellite cells. Satellite cells help to repair and regenerate muscle fibers. Morgan and Partridge note that skeletal muscle satellite cells “are normally quiescent in adult muscle, but act as a reserve population of cells, able to proliferate in response to injury and give rise to regenerated muscle and to more satellite cells.” [1]
In a quantification of acupuncture’s effective mechanisms, the Fujian Provincial Research Institution of Traditional Chinese Medicine researchers identified an important signaling pathway activated by acupuncture that is responsible for producing its therapeutic benefits. [2] Acupuncture successfully reduced apoptotic (cell death) changes and improved the levels of paired box gene 3 (PAX3) and 7 (PAX7). PAX3 and PAX7 are important indicators for identifying satellite cell proliferation and differentiation.
PAX3 is expressed in muscle progenitor cells and PAX7 is expressed mainly in satellite cells. Skeletal muscle progenitor and satellite cells play an important role in muscle cell proliferation. When muscle fibers are damaged, satellite cells differentiate into new muscle fibers, while progenitor cells proliferate and differentiate into satellite cells to ensure stable supplies. [3] Compared with the model group, the apoptotic index of the electroacupuncture (EA) group was significantly improved (P<0.05), indicating that acupuncture reduced muscle cell apoptosis. The expressions of PAX3 and PAX7 were significantly increased (both P<0.01), indicating that acupuncture increased the number of progenitor and satellite cells.
Acupuncture significantly increased the expression levels of phospho-AKT (P<0.05) and activated the IGF-1/PI3K/AKT pathway. Activated phospho-AKT (Ser473) regulates the mammalian target of rapamycin (mTOR), a cellular protein involved in cell proliferation, size/growth, and survival. [4] Modern research confirms that the IGF-1/PI3K/AKT signaling pathway plays an important role in promoting synthesis while inhibiting degradation of muscle proteins. [5]
Histological measurements produced similar results. Using HE stain, researchers found that the ratio of cross-sectional areas (denervated fibers to healthy fibers) and the ratio of fiber diameters (denervated fibers to healthy fibers) were significantly increased (both P<0.05). The researchers note, “Acupuncture increased the volume of muscle cells by promoting synthesis while inhibiting degradation of muscle proteins.”
Acupuncture
Intervention details for the acupuncture treatment group were provided. Treatment commenced one day after the denervated skeletal muscle atrophy model was created. After disinfection of the acupoint sites, a 0.25 mm × 30 mm disposable filiform needle was inserted perpendicularly into each acupoint, reaching a depth of 5–7 mm. Next, the needle at the Zusanli (ST36) point was connected to the positive electrode and the needle at the Shangjuxu (ST37) point was connected to the negative electrode. A 2/33 Hz disperse-dense wave was applied with an intensity level set to 1.5–2 mA. One 30-minute acupuncture session was administered daily. The laboratory rats received treatment for 5 consecutive days followed by a 2-day break each week, for a grand total of 4 weeks.
Electroacupuncture
In Traditional Chinese Medicine, denervation atrophy falls under the Wei Bing (wilting disease) class of disorders. In this investigation, the denervation atrophy model was made by cutting the hindlimb sciatic nerve of laboratory rats. According to TCM theory, acupuncture at points on the foot Yangming stomach meridian treats the Wei Bing problem. Modern research confirms that low-frequency (2–20 Hz) electroacupuncture produces superior outcomes in repairing denervation atrophy compared with high-frequency (100 Hz) electroacupuncture and manual acupuncture. [6] In an independent study, Sun et al. find a pulse or disperse-dense wave is more effective for repairing sciatic nerve injuries than a continuous wave. [7] Electroacupuncture used in this study involved the application of low-frequency, disperse-dense wave stimulation to Zusanli (ST36) and Shangjuxu (ST37).
Human Clinical Trial
In related research, Huang et al. combined electroacupuncture with a conventional rehabilitation training program. [8] They found that the combined therapy successfully alleviated quadricep atrophy while improving knee function in human subjects. Two groups were compared. Each received an identical rehabilitation training program. The treatment group also received electroacupuncture. All patients had quadricep atrophy after knee surgery.
True acupuncture produced superior patient outcomes including improvements in muscle strength, quadriceps angles, thigh circumference, knee range of motion, and Lysholm scores. The quadricep angle is a measurement used to assess the alignment of the knee joint. The Lysholm knee scale is used to evaluate knee stability and function. Four acupoints were used in the study:
- ST32 (Futu)
- ST34 (Liangqiu)
- ST35 (Dubi)
- ST36 (Zusanli)
Patients were instructed to rest in a supine position with the hips and knees bent at a raised angle. A 15–20 cm high pillow was put under the knees. After disinfection of the acupoint sites, a disposable filiform needle was inserted into each acupoint, reaching a depth of 1.5–2.0 cun. The mild reinforcement and attenuation (Ping Bu Ping Xie) manipulation technique was applied to each needle. Once a deqi sensation was obtained, the needles were connected to an electroacupuncture device.
Two pairs of electrodes were used. One was connected to Futu (+) and Zusanli (-). The other pair was connected to Liangqiu (+) and Dubi (-). A disperse wave (2–5 Hz) wave was applied with an intensity level set to patient tolerance levels. A 25-minute acupuncture session was conducted daily, for a total of 7 days.
Summary
The results of the aforementioned research indicates that acupuncture is an effective treatment modality for skeletal muscle atrophy. According to the research, common protocols involve the application of acupoints on the Yangming stomach meridian for this condition. In addition,
researchers demonstrate that electroacupuncture repairs and regenerates muscle fibers by activating the IGF-1/PI3K/AKT signaling pathway.
Notes
[1] Morgan, Jennifer E., and Terence A. Partridge. "Muscle satellite cells." The international journal of biochemistry & cell biology 35, no. 8 (2003): 1151-1156.
[2] Chen X, Ye XR, Huang XQ. Effect of electroacupuncture on denervated skeletal muscle atrophy and expression of IGF-1/PI3K/AKT in rats [J]. Chinese Acupuncture and Moxibustion, 2018,38(12):1311-1317.
[3] Xu JG, Gu YD, Li JF. Experimental study of rat denervated skeletal muscle atrophy [J]. Journal of Shanghai Medical University, 1999, 26(4): 265-268.
[4] Yip WK, Leong VC, Abdullah MA, Yusoff S, Seow HF. Overexpression of phospho-Akt correlates with phosphorylation of EGF receptor, FKHR and BAD in nasopharyngeal carcinoma[J], Oncol Rep. 2008 Feb;19(2):319-28.
[5] Latres E, Amini AR, Amini AA, et al. Insulin-like growth factor-1 (IGF-1) inversely regulates atrophy-induced genes via the phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway[J]. J Biol Chem, 2005, 280(4): 2737-2744.
[6] Li QW, Yisidatoulawo, Guo Y et al. Effects of electroacupuncture at different frequencies on morphological changes of nervous tissues and electromyogram of skeletal muscles in the rat with injury of sciatic nerve[J]. Chinese Acupuncture, 2005, 25(3): 73-76.
[7] Sun YC. Experimental study on the repair of sciatic nerve injury in rats by different waveforms, frequency, stimulation intensity and time of electroacupuncture [D]. Harbin: Heilongjiang University of Traditional Chinese Medicine, 2005.
[8] Huang WZ. Electroacupuncture combined with rehabilitation training to combat ACT reconstruction clinical studies of postoperative quadriceps atrophy [D]. Guangzhou University of Traditional Chinese Medicine.
