EFFECTS OF LOW-LEVEL LASER COMBINED SWIMMING EXERCISE ON MUSCLE ATROPHY IN DIABETIC MICE WITH PERIPHERAL ARTERY OCCLUSION

Background: Patients with diabetes mellitus (DM) are at high risk of peripheral arterial occlusion disease (PAOD) in lower extremities, and it could cause muscle atrophy. Low-level laser therapy (LLLT) has shown beneficial effects on damaged vascular. It is also well established that exercise training can decelerate muscle atrophy.

Purpose: We proposed LLLT combined swimming exercise (SE) can enhance angiogenesis and decrease muscle atrophy on diabetic mice with peripheral artery occlusion.

Methods: Thirty C57/BL6 mice were divided into 5 groups: control, DM, DM+LLLT, DM+SE, and DM+LLLT+SE; DM was induced by intraperitoneal injection with 50mg/kg streptozotocin. Left femoral artery ligation was performed later to mimic PAOD. For LASER treatment, mice were exposed to Al-GaInP-diode laser, 660 nm wavelength, 3.18 mW/cm2 for 10 minutes. Exercise training was conducted with swimming exercise for 25 min. Both treatment were performed 15 sessions, a total of 30 days. After sacrificed, gastrocnemius muscles were collected, weighed, and analyzed with immunofluorescence for muscle fiber are. Protein extract was analyzed by Western blot for signals related to muscle atrophy/hypertrophy and agiogenesis.

Results: After LASER and exercise intervention, blood perfusion and muscle weight of DM+LLLT+SE groups are higher than DM group. Immunofluorescence staining showed a significant decrease in big-size muscle fibers in DM group compared to DM+LLLT and DM+LLLT+SE group. Western blot showed a significant increase in mTOR phosphorylation, as well as p-eNOS, in DM+LLLT and DM+LLLT+SW groups.  In AKT phosphorylation and VEGF level,  no statistical difference was found among groups.

Conclusion(s): Low level LASER combine exercise training can decrease ischemia-induced muscle atrophy in diabetic mice. 

Implications: Low level LASER combine exercise significantly improved neovascularization, perfusion and delay muscle atrophy on ischemic limbs of diabetic mice. Considering the additional benefits, physiotherapist can refer to low level LASER to enhance the efficacy of exercise treatment in routine clinical practice.

Funding, acknowledgements: This study was supported by CMU107-S-25 from the China Medical University, Taiwan.

Keywords: peripheral arterial disease, Low-level laser therapy, muscle atrophy

Topic: Electrophysical & isothermal agents

Did this work require ethics approval? Yes

Institution: China Medical University, Taiwan

Committee: Affidavit of Approval of Animal Use Protocol

Ethics number: CMUIACUC-2019-128