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2022, Vol. 26 ›› Issue (14): 2184-2189Effect of uniaxial fatigue exercise on patellofemoral cartilage injury in a rabbitTan Xinfang1, Guo Yanxing2, Qin Xiaofei2, Zhang Binqing2, Zhao Dongliang2, Pan Kunkun2, Li Yuzhuo2, Chen Haoyu2
Abstract: BACKGROUND: There is a high incidence of patellofemoral cartilage injury in clinical practice. However, the current research on its etiology is insufficient. Hyperactivity is one of the pathological mechanisms widely recognized in clinic, and understanding the occurrence and development of patellofemoral injury is of great significance. OBJECTIVE: To study the effect of uniaxial fatigue exercise on the patellofemoral articular cartilage, and to explore patellofemoral cartilage injuries caused by fatigue in rabbits, so as to provide an experimental basis for understanding the effect of hyperactivity on patellofemoral cartilage lesions. METHODS: Eight New Zealand white rabbits were adaptively fed for 1 week. The right knee of each rabbit was selected as the experimental side and the left knee as the control side. The right knee was fixed on a modeling machine for uniaxial fatigue exercise, and the activity angle was set to be 0°-95° and the activity frequency was set at 60 beats per minute, 90 minutes a day, for 2 weeks. The left knee of each rabbit was untreated. After modeling, MRI images of the rabbit knee joints were collected. The animals were then sacrificed and sampled, and the cartilage tissue sections of the patellofemoral joint were observed and assessed by the Mankin score. RESULTS AND CONCLUSION: The patellar cartilage of the experimental side was significantly damaged. After 2 weeks of uniaxial fatigue exercise, the patellar cartilage of the experimental side had dull color, visible fissures, rough surface, and hyperplasia at the edge of the patellofemoral interface, while no obvious cartilage degeneration was observed on the control side. The results of knee MRI showed that the signal intensity of the patellar cartilage on the experimental side was heterogeneous. Hematoxylin-eosin staining results revealed that the cartilage surface of the experimental side was not smooth, and chondrocyte proliferation, disarrangement, and multiple tidal lines were observed under a light microscope. The Mankin score of the experimental side was significantly higher than that of the control side (P < 0.05). These findings indicate that 2-week uniaxial fatigue exercise can cause mild damage to the cartilage of the patellofemoral joint in rabbits, accompanied by pathological changes such as cartilage swelling and fissures. Key words:patellofemoral joint, cartilage, chondromalacia patellae, uniaxial fatigue exercise, animal model, pathology |