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- Author or Editor: Ned Williams x
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Abstract
Objective—To evaluate biocompatibility and effects of implantation of 3-dimensional chondrocyte-agarose autografts in tibial defects in rabbits and to compare in vitro and in vivo chondrocyte-agarose constructs with respect to cell viability, differentiation, and matrix production.
Animals—24 adult New Zealand White rabbits.
Procedure—Three-dimensional constructs with (grafted group) or without (control group) autogenous chondrocytes were implanted into tibial defects of rabbits and cultured in vitro. During an 8-week period, defects were evaluated radiographically, grossly, histologically, biochemically, and immunohistochemically. In vitro constructs were evaluated histologically, biochemically, and immunohistochemically.
Results—Tibial defects had significantly higher radiographic densitometry values at 4 and 6 weeks after implantation in grafted group rabbits, compared with control group rabbits. Number of observed centers of endochondral ossification was significantly greater in defects of grafted group rabbits, compared with control group rabbits. On day 14, glycosaminoglycan concentration was significantly higher in tibial defects of grafted group rabbits, compared to defects of control group rabbits or in vitro constructs. At weeks 2, 4, and 8, glycosaminoglycan concentrations were significantly lower in the in vitro control constructs, compared with other groups. Collagen type I was present in bone and bony callous in defects of grafted and control group rabbits. Collagen type II was identified in cartilaginous tissues of grafted and control group rabbits. Collagen type X was associated with hypertrophic chondrocytes. Only type II collagen was found in the in vitro chondrocyte constructs.
Conclusion and Clinical Relevance—Chondrocyte-agarose grafts are biocompatible in large tibial defects and appear to provide a cell source for augmenting endochondral ossification. (Am J Vet Res 2003;64:12–20)
Abstract
OBJECTIVE: To assess the relationship between histologic degeneration of cranial cruciate ligaments (CCLs) and severity of synovitis and ligament vascularity.
SAMPLE: CCL and synovium from 59 stifle joints (53 dogs). PROCEDURES: CCL and synovium specimens were obtained from stifle joints of juvenile (15 joints; 12 dogs) and adult (25 joints; 22 dogs) dogs with intact CCLs and dogs with CCL rupture (rCCL; 19 joints; 19 dogs). Vascular density and degenerative changes of the CCL core region and severity of synovitis were semiquantitatively evaluated. Relationships were analyzed by use of a random effects model to account for correlated specimens.
RESULTS: Mean ± SD modified Bonar scores (scale, 0 to 9) of adults (4.85 ± 0.44) and dogs with rCCL (5.69 ± 0.49) were significantly higher than scores of juveniles (1.13 ± 0.55). Vascularity scores (scale, 0 to 3) were significantly higher for juveniles (3.00 ± 0.24) than for adults (1.53 ± 0.27) and dogs with rCCL (0.78 ± 0.23). Synovitis scores were not significantly different among groups. There was a significant negative relationship between modified Bonar scores and vascularity scores for juveniles and adults and for adults and dogs with rCCL when controlling for age, but there was not a significant relationship between modified Bonar scores and synovitis scores. There was a significant relationship between modified Bonar scores and body weight of adults.
CONCLUSIONS AND CLINICAL RELEVANCE: Poor blood supply to the core region could be an important underlying condition for spontaneous degeneration of the CCL in at-risk dogs.
