Immunohistochemistry of articular cartilage from immature beagle dogs dosed with difloxacin

• Published in: Toxicologic pathology Vol. 25; no. 5; p. 475
• Main Authors: Burkhardt, J E, Förster, C, Lozo, E, Hill, M A, Stahlmann, R
• Format: Journal Article
• Language: English
• Published: United States 01.09.1997
• Subjects: Administration, Oral; Animals; Anti-Infective Agents - toxicity; Antigens, CD - metabolism; Arthritis, Experimental - chemically induced; Arthritis, Experimental - metabolism; Arthritis, Experimental - pathology; Cartilage, Articular - drug effects; Cartilage, Articular - metabolism; Cartilage, Articular - pathology; Ciprofloxacin - analogs & derivatives; Ciprofloxacin - toxicity; Collagen - metabolism; Dogs; Extracellular Matrix - drug effects; Extracellular Matrix - metabolism; Extracellular Matrix - pathology; Fibronectins - metabolism; Fluoroquinolones; Humerus - drug effects; Humerus - metabolism; Immunohistochemistry - methods; Integrin alphaV
• ISSN: 0192-6233
• DOI: 10.1177/019262339702500508

Effects of the fluoroquinolone difloxacin on articular-epiphyseal cartilage in growing beagle dogs have been described by light microscopic, electron microscopic, and biochemical methods. Here we present data from an immunohistochemistry study with humeral head cartilage from 3-mo-old beagle dogs after treatment with 1 or 2 oral doses of 300 mg difloxacin/kg body weight. Dogs were euthanatized either 24 hr (single dose) or 48 hr (2 doses) after onset of dosing, and cartilage tissue was stored at -90 degrees C until it was studied by immunohistochemistry. Antibodies against matrix components (collagen II, fibronectin) as well as antibodies against cellular structures (integrins) were used. After single-dose treatment (24-hr group), cartilage lesions such as clefts were not observed, but increased staining for fibronectin was found in cartilage samples from 5 of 6 animals. Markedly increased staining for fibronectin was also demonstrated in the vicinity of clefts within cartilage of all animals of the 48-hr group. Collagen II staining was homogeneously distributed in cartilage from controls and was slightly reduced in territorial matrix in 2 of 6 dogs of the 48-hr group. Integrin staining on chondrocytes was not significantly affected by difloxacin under the given conditions with the exception of a slight reduction of the alpha v integrin chain in 1 of 5 dogs of the 48-hr group. Overall, the most important results is the finding that fibronectin was a sensitive immunohistochemical marker for change in cartilage samples due to difloxacin treatment in dogs.