Therapeutic Effects of Invasive Laser Acupuncture on Monosodium Iodoacetate-Induced Osteoarthritis Rats

Background: Knee osteoarthritis (KOA) is a prevalent degenerative joint disease. Laser acupuncture is a popular treatment option within acupuncture for KOA. This study aimed to assess the effectiveness of invasive laser acupuncture in mitigating osteoarthritis (OA) progression compared with manual acupuncture. Methods: A rat model of OA was induced with monosodium iodoacetate (MIA). Forty-eight Sprague Dawley rats weighing 240–280 g were randomly divided into six groups: control, OA, sham laser, manual acupuncture, and 650 and 830 nm invasive laser acupuncture. Treatments lasted 8 weeks. Mechanical allodynia was tested once a week. Safranin O/Fast Green and H&E staining were used to assess the cartilage damage. Micro-computed Tomography imaging was used to confirm the influence on the subchondral bone. Results: OA rats exhibited increased pain, inflammation, and bone damage. Both 650 and 830 nm laser acupuncture treatments reduced these pathological changes and protected the cartilage and surrounding tissues. Paw withdrawal threshold scores were also improved. The 830 nm group showed superior subchondral bone preservation compared with the OA group, with improved bone volume to tissue volume ratio (34.85 ± 1.21, p < 0.01) and trabecular separation (0.03 ± 0.01, p < 0.05), thus inhibiting abnormal bone remodeling. Conclusion: This study suggests that invasive laser acupuncture, particularly 830 nm, is superior to 650 nm and manual acupuncture and potentially leads to slower disease progression, reduced pain, and improved joint function by alleviating inflammation and bone remodeling.