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

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

Affiliations

  • 1 Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong SAR, China. Electronic address: tianxiang.fan@connect.polyu.hk.
  • 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: yuen.tsang@polyu.edu.hk.
  • 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: ziyuchen@pkuszh.com.
  • 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: lixiangxue@hsc.pku.edu.cn.
  • 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: shidongquan@nju.edu.cn.
  • 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: wayne.wang@polyu.edu.hk.
  • 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: benny.cheung@polyu.edu.hk.
  • 11 Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong SAR, China. Electronic address: marco.pang@polyu.edu.hk.
  • 12 Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong SAR, China. Electronic address: yeli@link.cuhk.edu.hk.
  • 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: amy.fu@polyu.edu.hk.
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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