Efficacy of femtosecond lasers for application of acupuncture therapy

Lasers in Medical Science, Dec 2016

Acupuncture treatment utilizes the stimulation of metal acupuncture needles that are manually inserted into a living body. In the last decades, laser light has been used as an alternative to needles to stimulate acupuncture points. We previously reported suppression of myostatin (Mstn) gene expression in skeletal muscle by means of femtosecond laser (FL) irradiation, after electroacupuncture, in which acupuncture needles are stimulated with a low-frequency microcurrent. The purpose of the study here was to investigate the efficacy of FL irradiation in mouse skeletal muscle with regard to protein synthesis. After irradiation of the hindlimbs, we first analyzed Mstn gene expression and Mstn protein level in the skeletal muscle. We then evaluated phosphorylation of the mammalian target of rapamycin (mTOR) and its downstream target 70-kDa ribosomal protein S6 kinase (p70S6K). The results showed that FL irradiation significantly reduced the amount of Mstn protein and enhanced the phosphorylation of p70S6K in of the mTOR/S6K signaling pathway. We suggest that FL irradiation activated the protein synthetic pathway in the skeletal muscle. In conclusion, we determined that FL irradiation can serve as an alternative for acupuncture needles and has the potential of being a new non-invasive acupuncture treatment of skeletal muscle.

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Efficacy of femtosecond lasers for application of acupuncture therapy

Lasers Med Sci Efficacy of femtosecond lasers for application of acupuncture therapy Mika Ohta 0 1 2 3 4 Yoichiroh Hosokawa 0 1 2 3 4 Naoya Hatano 0 1 2 3 4 Aki Sugano 0 1 2 3 4 Akihiko Ito 0 1 2 3 4 Yutaka Takaoka 0 1 2 3 4 0 Graduate School of Materials Science, Nara Institute of Science and Technology , Nara 630-0912 , Japan 1 Genome Science Research Unit, Life Science Research Center, Kobe Tokiwa University , Kobe 653-0838 , Japan 2 Division of Medical Informatics and Bioinformatics, Kobe University Hospital , Kobe 650-0017 , Japan 3 Department of Pathology, Kindai University Faculty of Medicine , Osaka 589-8511 , Japan 4 The Integrated Center for Mass Spectrometry, Kobe University Graduate School of Medicine , Kobe 650-0017 , Japan Acupuncture treatment utilizes the stimulation of metal acupuncture needles that are manually inserted into a living body. In the last decades, laser light has been used as an alternative to needles to stimulate acupuncture points. We previously reported suppression of myostatin (Mstn) gene expression in skeletal muscle by means of femtosecond laser (FL) irradiation, after electroacupuncture, in which acupunct u r e n e e d l e s a r e s t i m u l a t e d w i t h a l o w - f r e q u e n c y microcurrent. The purpose of the study here was to investigate the efficacy of FL irradiation in mouse skeletal muscle with regard to protein synthesis. After irradiation of the hindlimbs, we first analyzed Mstn gene expression and Mstn protein level in the skeletal muscle. We then evaluated phosphorylation of the mammalian target of rapamycin (mTOR) and its downstream target 70-kDa ribosomal protein S6 kinase (p70S6K). The results showed that FL irradiation significantly reduced the amount of Mstn protein and enhanced the phosphorylation of p70S6K in of the mTOR/S6K signaling pathway. We suggest that FL irradiation activated the protein synthetic pathway in the skeletal muscle. In conclusion, we determined that FL irradiation can serve as an alternative for acupuncture needles and has the potential of being a new non-invasive acupuncture treatment of skeletal muscle. Femtosecond laser; Acupuncture therapy; Skeletal muscle; Myostatin; mTOR; p70S6K Introduction Low-level lasers have been used in laser acupuncture, and their analgesic effects have been reported [ 1, 2 ]. Low-level lasers normally generate heat during irradiation, whereas heat generation at femtosecond laser (FL) focal spots is suppressed because of effective conversion of energy to kinetic waves [3]. In our previous FL study, we did not detect heat denaturation in animal tissues after irradiation [ 4 ]. The damage caused by the irradiation was observed in the epidermis and dermis, and the diameter of the damaged area and its depth were approximately 400 and 1100 μm, respectively. Such effects on animal tissue are similar to those of acupuncture treatment with acupuncture needles. Therefore, we believed that the FL was a good candidate for laser acupuncture. We also elucidated expression of the Mstn gene after electroacupuncture (EA) treatment, which is one type of acupuncture stimulation [ 5 ]. Mstn, a member of the transforming growth factor-β superfamily, is a potent negative regulator of skeletal muscle mass [ 6 ]. Mstn has inhibited activation of satellite cells in skeletal muscle [ 7 ]. Mstn inactivation induced skeletal muscle hypertrophy in humans and mice [ 8, 9 ]. Our previous study indicated that EA treatment suppressed Mstn expression, which led to a satellite cell-related proliferative reaction and repair in skeletal muscle [5]. Other results showed that EA-induced Mstn gene suppression may help prevent muscle atrophy in mice [ 10 ]. We subsequently found suppression of expression of the Mstn gene in mouse skeletal muscle after FL irradiation, just as with EA [ 4, 11 ]. On the basis of the results of our previous studies, we expected activation of the protein synthetic pathway because Mstn inhibits activation of the Akt/mTOR pathway [ 12, 13 ]. The Akt/mTOR pathway regulates protein synthesis and is upregulated during skeletal muscle hypertrophy. The mTOR/ S6K pathway includes the 70-kDa ribosomal protein S6 kinase (p70S6K) protein downstream, and the protein functions in the mTOR/S6K signaling pathway, which regulates protein synthesis and cell growth [14]. This study aimed to elucidate the efficacy of FL irradiation of mouse skeletal muscle. We investigated Mstn gene expression, the amount of Mstn protein, and phosphorylation of mTOR and p70S6K after irradiation. Materials and methods Animals and treatment C57BL/6J male mice, 8 weeks old, were purchased from Charles River Laboratories, Yokohama, Japan. We divided the mice into three groups: controls, n = 5; acupuncture (ACP) stimulation, n = 6; and FL, n = 6. After anesthesia to all the three groups, hair on the hind legs of FL mice was removed by using hair removal cream, and FL treatment focused on the lower legs. A single-shot (...truncated)


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Mika Ohta, Yoichiroh Hosokawa, Naoya Hatano, Aki Sugano, Akihiko Ito, Yutaka Takaoka. Efficacy of femtosecond lasers for application of acupuncture therapy, Lasers in Medical Science, 2016, pp. 2167-2171, Volume 32, Issue 9, DOI: 10.1007/s10103-016-2124-3