Effects of 650 nm laser acupuncture on cartilage, bone, and skeletal muscle in osteoarthritis

Abstract

This study evaluated the therapeutic effects of 650 nm laser acupuncture at 10 mW and 20 mW in a monosodium iodoacetate (MIA) induced osteoarthritis (OA) rat model. OA was induced by intra-articular injection of MIA, and laser acupuncture was applied to GB34 and GB39 twice weekly for four weeks. Cartilage preservation was assessed by Safranin-O staining, pain by hind paw weight distribution, bone structure by micro-CT analysis of bone volume fraction, trabecular volume, and cortical thickness, and muscle condition by histology and wet weight of the gastrocnemius and quadriceps. Both laser treatments reduced cartilage degeneration and improved weight-bearing. The 10 mW group showed greater improvements than the 20 mW group, including higher proteoglycan content, better bone structural parameters, and greater muscle mass. These results indicate that 10 mW laser acupuncture is more effective than 20 mW in reducing joint damage and preserving musculoskeletal tissue. The findings support the use of low-power laser acupuncture as a non-invasive treatment for OA. The study also shows that higher laser power does not necessarily lead to better outcomes, highlighting the need for appropriate dose selection. Further studies are needed to assess long-term effects and investigate underlying mechanisms.