Effects of exercise on chondrocyte viability and subchondral bone sclerosis in the distal third metacarpal and metatarsal bones of young horses
ABSTRACT The objective was to determine the effects of early exercise on the articular cartilage and subchondral bone at specific sites of the distal third metacarpal and metatarsal bones of 12 young Thoroughbred horses allowed free choice exercise at pasture. Six of the horses had additional controlled exercise 5 days per week from mean age of 21 ± 20 days of age (range: 3–83 days) until 17.1 months of age. Confocal laser scanning microscopy was used to quantify viable and non-viable chondrocytes. Proteoglycan scoring and modified Mankin scoring was performed and subchondral bone mineral density measured by computed tomography. The number of viable chondrocytes was significantly greater in the conditioned group, which also had a higher Safranin O/Fast Green (SOFG) score than did the group which could exercise only at pasture. There was no difference in mean bone mineral density between groups, nor was there relationship between subchondral bone mineral density and chondrocyte viability. The apparent beneficial effects of early conditioning exercise may support the use of exercise to optimise development of articular cartilage in young individuals.
Article: Assessment of bone response to conditioning exercise in the radius and tibia of young thoroughbred horses using pQCT.[show abstract] [hide abstract]
ABSTRACT: To assess the effect of conditioning exercise on bone parameters at multiple sites in the radius and tibia of young Thoroughbred horses. The left and right radius and tibia were obtained from twelve horses, six of which had received conditioning exercise and six which formed the control group. Each bone was scanned at 5% intervals along its entire length using pQCT. Bone strength, bone area and periosteal circumference were significantly greater for the group of conditioned horses in both the radius and tibia. Volumetric bone mineral density was lower while bone mineral content, endocortical circumference and polar moment of inertia were higher in the conditioned group of horses but the significance of these differences varied between the two bones. Cortical thickness was not significantly different between the groups in either bone. Conditioning exercise stimulated a significant increase in the strength of both bones that could be attributed mainly to an increase in bone size, rather than differences in bone mineral content or density. The radius and tibia exhibited differences in the significance of changes in several bone parameters suggesting that not all bones respond in an identical fashion to imposed exercise.Journal of musculoskeletal & neuronal interactions 09/2010; 10(3):199-206. · 2.00 Impact Factor