Abstract | BACKGROUND: Light alteration affects the internal environment and metabolic homeostasis of the body through circadian rhythm disorders (CRD). CRD is one of the factors that induce and accelerate osteoarthritis (OA). Therefore, the aim of this study was to evaluate the effects of continuous dark-light (DL) cycle on joint inflammation, bone structure, and metabolism in normal and OA Sprague-Dawley (SD) rats. METHODS: RESULTS: DL cycle significantly inhibited body weight gain in normal and OA rats. The levels of proinflammatory factors in the peripheral blood circulation and degradation enzymes in the cartilage were significantly decreased in OA+DL rats. DL cycle significantly destroyed the structure of subchondral bone in hindlimbs of OA rats and reduced trabecular bone numbers. The decrease of bone mineral density (BMD), percent bone volume with respect to total bone volume (BV/TV), trabecular number (TB.N), osteoclast number, and mineralization could also be found. The ratio of the receptor activator of nuclear factor-kappa B ligand/ osteoprotegerin (RANKL/OPG) in the bone marrow of OA rats was markedly increased under DL, along with the activation of the mononuclear/phagocyte system. The expression of representative clock proteins and genes BMAL1, PER3, and CRY1 were markedly changed in the tissues of OA+DL rats. CONCLUSIONS: These results suggested that DL cycle dampened the arthritis and promoted bone resorption and bone mass loss. DL cycle affects bone turnover by regulating osteoclast production in osteoarthritic rats.
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Authors | Xiaopeng Song, Mingchao Zhao, Jilang Tang, Tianwen Ma, Hui Bai, Xinyu Wang, Lin Liu, Ting Li, Xinyu Xu, Xuanbo Sheng, Binger Zhao, Yingying Wang, Tiantian Wang, Yingchao Guo, Xinmin Zhang, Li Gao |
Journal | Arthritis research & therapy
(Arthritis Res Ther)
Vol. 24
Issue 1
Pg. 158
(06 28 2022)
ISSN: 1478-6362 [Electronic] England |
PMID | 35765090
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Copyright | © 2022. The Author(s). |
Chemical References |
- ARNTL Transcription Factors
- CLOCK Proteins
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Topics |
- ARNTL Transcription Factors
- Animals
- CLOCK Proteins
- Osteoarthritis
(metabolism)
- Photoperiod
- Rats
- Rats, Sprague-Dawley
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