The effect of body mass and physical activity on the development of guinea pig osteoarthrosis.

We quantitatively evaluated the morphological and biochemical effects of body mass and physical activity on spontaneously developing guinea pig osteoarthrosis (OA). 6-month-old male guinea pigs were allocated to 3 groups: controls (C) living under standard laboratory conditions with food ad libitum; mobilized animals (M) allowed unrestricted motion in large rooms with food ad libitum; and a diet group (D) weight-matched with the M-group. At 9- and 12-months of age they were killed and the left proximal tibia was processed for quantitative histology and the right tibial articular cartilage for analyses of glycosaminoglycan (GAG).

Distribution of chondroitin 4-sulfate epitopes (2/B/6) in various zones and compartments of articular cartilage in guinea pig osteoarthrosis.

We studied changes in the morphology of tibial articular cartilage in early guinea pig osteoarthrosis (OA) at 6 and 12 months of age with quantitative light microscopy, and the distribution of chondroitin-4-sulfate with quantitative ultrastructural immunolabeling, using the 2/B/6 epitope. Labeling was correlated to previous chromatography findings concerning proteoglycan (PG) concentration in animals of the same age. The cell volume fraction had decreased at 12 months in the superficial zone of cartilage with OA (medial condyle) as well as in cartilage without OA (lateral condyle), being lower medially than laterally.