Chinese Journal of Tissue Engineering Research ›› 2024, Vol. 28 ›› Issue (28): 4522-4527.doi: 10.12307/2024.464

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Pulsed electromagnetic fields inhibit knee cartilage degeneration in aged rats

Yin Linwei1, 2, 3, Huang Xiarong1, 2, 3, Sun Guanghua1, 2, 3, Liu Jing1, 2, 3, Zhong Peirui1, 2, 3, Wang Jinling1, 2, 3, Chen Jiaqian1, 2, 3, Wen Xing1, 2, 3, Gan Shaoting1, 2, 3, Hu Wentao1, 2, 3, Li Mengmeng1, 2, 3, Zhou Jun1, 2, 3, 4   

  1. 1Department of Rehabilitation, 2Rehabilitation Medicine Center, 3Rehabilitation Laboratory, the First Affiliated Hospital of Hengyang Medical School, University of South China, Hengyang 421001, Hunan Province, China; 4Key Laboratory of Rehabilitation Medicine, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, China
  • Received:2023-07-12 Accepted:2023-09-06 Online:2024-10-08 Published:2023-11-27
  • Contact: Zhou Jun, MD, Doctoral supervisor, Chief physician, Department of Rehabilitation, Rehabilitation Medicine Center, Rehabilitation Laboratory, the First Affiliated Hospital of Hengyang Medical School, University of South China, Hengyang 421001, Hunan Province, China; Key Laboratory of Rehabilitation Medicine, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, China
  • About author:Yin Linwei, Therapist-in-charge, Department of Rehabilitation, Rehabilitation Medicine Center, Rehabilitation Laboratory, the First Affiliated Hospital of Hengyang Medical School, University of South China, Hengyang 421001, Hunan Province, China
  • Supported by:
    National Natural Science Foundation of China, No. 81973917 (to ZJ); Hunan Provincial Clinical Medical Technology Innovation Guidance Project, No. 2021SK51805 (No. ZJ); Hunan Provincial Natural Science Foundation, No. 2021JJ40493 (to HXR); Hunan Provincial Health Commission Key Project, No. 202103060198 (to ZJ); Project 4310 of Clinical Medicine of University of South China (to ZJ); Key Sub-project of University of South China, No. USCKF201902K02 (to ZJ)

Abstract: BACKGROUND: Pulsed electromagnetic fields, as an important physical therapy, are exactly effective in the treatment of osteoarthritis, but the mechanism has not been fully clarified.
OBJECTIVE: To observe the effect of pulsed electromagnetic field on the degeneration of knee joint cartilage in aged rats.
METHODS: Eight 6-month-old Sprague-Dawley rats were selected as the young group and were subjected to normal diet with no treatment. Sixteen 22-month-old Sprague-Dawley rats were randomly divided into old group (n=8) and pulsed electromagnetic field group (n=8). The rats in the pulsed electromagnetic field group were subjected to a pulsed electromagnetic field intervention, once a day, 5 days per week for continuous 8 weeks. The rats in the old group were given no treatment. All rats were anesthetized and executed after 8 weeks for the detection of relevant indexes.
RESULTS AND CONCLUSION: Compared with the young group, serum type II collagen C-terminal peptide level was increased in the old group (P < 0.05); compared with the old group, serum type II collagen C-terminal peptide level was decreased in the pulsed electromagnetic field group (P < 0.05). Micro-CT showed that the bone volume fraction, bone mineral density, and number of bone trabeculae decreased (P < 0.05) and the trabecular separation increased 
(P < 0.05) in the tibia of rats in the aged group compared with the young group; and the bone volume fraction, bone density, and number of trabeculae increased (P < 0.05) and the trabecular separation decreased (P < 0.05) in the tibia of rats in the pulsed electromagnetic field group compared with the aged group. The tibial plateau Safranin O-fast green staining showed that the articular cartilage structure of rats in the aged group was disorganized, and the number of chondrocytes was obviously reduced, and the tidal line could not be distinguished. The above results were improved in the pulsed electromagnetic field group. RT-qPCR and western blot assay showed that the mRNA and protein expression levels of matrix metalloproteinase 1, matrix metalloproteinase 13, P53 and P21 in the articular cartilage and subchondral bone of rats were elevated in the aged group compared with the young group (P < 0.05) and decreased in the pulsed electromagnetic field group compared with the old group (P < 0.05). To conclude, pulsed electromagnetic fields may improve osteoarthritis in aged rats by inhibiting chondrocyte senescence, alleviating articular cartilage degradation and inhibiting subchondral bone osteoporosis through suppressing the expression of P53/P21. 

Key words: pulsed electromagnetic field, aged rat, knee osteoarthritis, articular cartilage degeneration, P53, P21

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