Department of Rehabilitation and Orthopaedics, Medical University of Lublin, 20-059 Lublin, Poland.
Department and Clinic of Animal Surgery, University of Life Sciences, 20-033 Lublin, Poland.
Int J Mol Sci. 2023 Feb 10;24(4):3540. doi: 10.3390/ijms24043540.
Osteoarthritis (OA) is one of the most prevalent diseases of the osteoarticular system. Progressive destruction of joints is accompanied by development of pathological changes in the muscle tissue, i.e., weakening, atrophy, and remodelling (sarcopenia). The aim of the present study is to assess the impact of physical activity on the musculoskeletal system in an animal model of early degenerative lesions in the knee joint. The study involved 30 male Wistar rats. The animals were allocated to three subgroups of 10 animals each. Each animal from the three subgroups received sodium iodoacetate by injection into the patellar ligament of the right knee joint, whereas saline was administered through the patellar ligament in the left knee joint. The rats in the first group were stimulated to exercise on a treadmill. The animals in the second group were allowed to lead a natural lifestyle (no treadmill stimulation). In the third group, all parts of the right hind limb muscle were injected with Clostridium botulinum toxin type A. The study demonstrated that, compared to the active rats, bone density in the immobilised rats decreased, as indicated by the densitometric assessment of the whole body and the examination of rats' hind limbs and knee joints alone. This clearly evidenced the impact of physical activity on bone mineralisation. The weight of both fat and muscle tissues in the physically inactive rats was reduced. Additionally, the adipose tissue had higher weight in the entire right hind limbs, where monoiodoacetic acid was administered to the knee joint. The animal model clearly showed the importance of physical activity in the early stages of OA, as it slows down the process of joint destruction, bone atrophy, and muscle wasting, whereas physical inactivity contributes to progression of generalised changes in the musculoskeletal system.
骨关节炎（OA）是一种最常见的骨骼关节系统疾病。关节的进行性破坏伴随着肌肉组织的病理变化，即减弱、萎缩和重塑（肌肉减少症）。本研究的目的是评估膝关节早期退行性病变动物模型中身体活动对骨骼肌肉系统的影响。
研究涉及 30 只雄性 Wistar 大鼠。将动物分为三组，每组 10 只。三组动物的右膝关节髌韧带内均注射碘乙酸钠，左膝关节髌韧带内注射生理盐水。第一组动物在跑步机上进行刺激运动。第二组动物可自由活动（不进行跑步机刺激）。第三组动物的右后肢所有肌肉均注射 A 型肉毒梭菌毒素。
研究表明，与活跃的大鼠相比，固定的大鼠的骨密度降低，全身和单独检查大鼠的后肢和膝关节的骨密度评估证实了身体活动对骨矿化的影响。不活跃的大鼠的脂肪和肌肉组织的重量均减少。此外，在整个右后肢中，脂肪组织的重量更高，因为在膝关节中注射了单碘乙酸。动物模型清楚地表明了身体活动在 OA 早期的重要性，因为它可以减缓关节破坏、骨萎缩和肌肉减少的过程，而身体不活动则会导致骨骼肌肉系统的全身性变化的进展。
