Effects of aging and dietary restriction on the structural integrity of rat articular cartilage

The objectives of this study were to investigate the effects of aging and d iet restriction on the biomechanical properties of articular cartilage, usi ng a well-controlled rat model (Fischer 344). This animal model is recommen ded by the National Institute of Aging specifically to study aging and diet issues. nit: intrinsic biomechanical properties of articular cartilage wer e obtained using a creep indentation approach. The ages chosen (6, 12, 18, 24 months of age) correspond to approximate human ages of 20 to 80 years ol d. The diet regimen employed in this study used either an ad libitum fed gr oup or a group fed 60% of the mean food intake of the ad libitum group. The results demonstrate that, unlike bone, rat articular cartilage biomechanic al properties are not affected in a discernible manner by diet restriction, despite the fact that diet-restricted animals were significantly lighter i n terms of body weight. Age effects on biomechanical properties are found o nly at 6 and 12 months probably due to developmental reasons, but not at la ter ages. It appears that aging and diet restriction have profoundly differ ent effects on articular cartilage and bone. Another significant result of this study was to establish the rat as a suitable animal model to study car tilage biomechanical properties. Thus, the rat can be added to the list of animals that can be used to study structure-function and pathophysiological relationships in articular cartilage. (C) 2000 Biomedical Engineering Soci ety. [S0090-6964(00)00102-8].