This study was performed to determine glycosaminoglycan (GAG) concentration and immunohistochemical staining characteristics of type-I, -II, and -X collagen from cartilage affected by osteochondritis dissecans (OCD) in dogs.
31 dogs with OCD and 11 clinically normal purpose-bred dogs were included.
Cartilage samples were evaluated microscopically, and GAG content was determined. Immunohistochemical staining was performed for type-I, -II, and -X collagen. Sections were subjectively evaluated for location and intensity of staining.
Results: Cartilage affected by OCD had a variety of pathologic changes and significantly lower GAG concentrations than did normal cartilage. Normal cartilage had no detectable type-I collagen.
For dogs < 9 months of age, cartilage affected by OCD had significantly more type-I collagen but significantly less type-X collagen than did control cartilage. For dogs > 12 months of age, cartilage affected by OCD contained significantly more type-I collagen than did control cartilage.
There was a significant negative correlation between immunoreactivity of type-I collagen and that of type-II and -X collagen.
A significant positive correlation was found between immunoreactivity of type-II and -X collagen.
Thus, cartilage affected by OCD contains less GAG, more type-I collagen, and less type-X collagen, compared with normal cartilage. A direct correlation between these changes and the etiopathogenesis of OCD was not established.
Source: Tomlinson JL, Cook JL, Kuroki K, Kreeger JM, Anderson MA. (2001): Biochemical characterization of cartilage affected by osteochondritis dissecans in the humeral head of dogs. In: Am J Vet Res. 2001 Jun;62(6):876-81.
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