Wavelength-dependent photobiomodulation attenuates synovial inflammation in fibroblast-like synoviocytes and a collagenase-induced osteoarthritis model

  • J Photochem Photobiol B. 2025 Nov:272:113276. doi: 10.1016/j.jphotobiol.2025.113276.
Tianxiang Fan  1 ,  Peng Xia  2 ,  Safayet Ahmed  3 ,  Yuen H Tsang  4 ,  Zhi Yao  5 ,  Deli Wang  5 ,  Ziyu Chen  6 ,  Lixiang Xue  7 ,  Dongquan Shi  8 ,  Bo Wang  9 ,  Chi Fai Cheung  10 ,  Marco Y C Pang  11 ,  Ye Li  12 ,  Siu Ngor Fu  13
Affiliations
  • 1. Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong SAR, China. Electronic address: [email protected].
  • 2. Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong SAR, China.
  • 3. Department of Physics, Oregon State University, Corvallis, OR, USA.
  • 4. Department of Applied Physicals, The Hong Kong Polytechnic University, Hong Kong SAR, China. Electronic address: [email protected].
  • 5. Department of Bone and Joint Surgery, Peking University Shenzhen Hospital, Shenzhen, China.
  • 6. Department of Bone and Joint Surgery, Peking University Shenzhen Hospital, Shenzhen, China. Electronic address: [email protected].
  • 7. Cancer Center of Peking University Third Hospital, Center of Basic Medical Research, Institute of Medical Innovation and Research, Peking University Third Hospital, Beijing, China. Electronic address: [email protected].
  • 8. State Key Laboratory of Pharmaceutical Biotechnology, Department of Sports Medicine and Adult Reconstructive Surgery, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China. Electronic address: [email protected].
  • 9. State key laboratory of ultra-precision machining technology, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hong Kong SAR, China; Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hong Kong SAR, China. Electronic address: [email protected].
  • 10. State key laboratory of ultra-precision machining technology, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hong Kong SAR, China; Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hong Kong SAR, China. Electronic address: [email protected].
  • 11. Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong SAR, China. Electronic address: [email protected].
  • 12. Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong SAR, China. Electronic address: [email protected].
  • 13. Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong SAR, China; State key laboratory of ultra-precision machining technology, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hong Kong SAR, China. Electronic address: [email protected].
PMID: 41075743 DOI: 10.1016/j.jphotobiol.2025.113276
Abstract

Photobiomodulation (PBM) using light-emitting diodes (LEDs) has demonstrated promising anti-inflammatory effects in musculoskeletal disorders. However, the optimal parameters for modulating synovitis and joint degeneration in osteoarthritis (OA) remain unclear. This study aimed to examine the wavelength- and dose-dependent effects of PBM on inflammatory responses in fibroblast-like synoviocytes (FLS) and evaluate the in vivo therapeutic efficacy of selected wavelengths in a murine model of collagenase-induced OA (CIOA). Primary rat FLS were stimulated with TNF-α and irradiated using PBM at 625, 810, 940, or 1050 nm with fluences ranging from 13 to 78 J/cm2 (fixed irradiance of 44 mW/cm2). mRNA levels of IL-1β, IL-6, COX-2, and iNOS were quantified by RT-qPCR. The in vivo study involved daily PBM (810 or 940 nm at 39 J/cm2) for two weeks in CIOA mice, starting one week post-induction. Pain-related behavior was assessed weekly using the incapacitance test. Synovial inflammation and cartilage degradation were evaluated by histology and immunofluorescence staining for IL-1β and IL-6. Among tested parameters, 810 nm at 39 J/cm2 showed the most potent suppression of inflammatory gene expression in FLS. In vivo, 810 nm PBM significantly improved pain-related behavior by week 4, reduced synovitis and cartilage damage, and downregulated IL-1β and IL-6 expression in synovium. While 940 nm PBM also demonstrated anti-inflammatory effects in vitro, it did not show significant efficacy in vivo. These findings suggest that PBM at 810 nm exerts stronger anti-inflammatory and chondroprotective effects in inflammatory OA compared with 940 nm, supporting its potential as a non-pharmacological intervention for inflammatory OA phenotypes.

Keywords
Osteoarthritis; Photobiomodulation; Synovial inflammation; Wavelength-dependent effect.
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