Morphological Investigation of Cavity Formation in Articular Cartilage Induced by Oiloxacin in Rats

Morphological Investigation of Cavity Formation in ArticularCartilage Induced by Ofloxacin in Rats. Kato, M., andOnodera,T.( 1988).Fundam. Appl Toxwol. 11, 110–119. Ofloxacin,a quinolone antibacterial agent, induced blisters and/or erosionsin the articular cartilage of the humeral trochlea, femoralcondyle, and femoral head of immature rats. Histologically,cavity formation was seen in the middle zone of the articularcartilage. Changes were detected as early as 5 hr after a singleoral administration of 1000 or 3000 mg/kg. These changes werecharacterized by condensation, atrophy, and deformation of thenuclei of chondrocytes distributed in the middle zone. In suchnuclei, aggregation of heterochromatin was observed. Degeneratedcells with vacuolated and partially disintegrated cytoplasmswere also seen in this zone. These lesions were followed byedema of the matrix accompanied with markedly decreased stainabilitywith safranin-O, and a cavity was formed later by liquefactionof the cartilage. The changes were reversible, with reboundingoccurring even with continued treatment with ofloxacin. Theproliferation of chondrocytes around the lesion chiefly contributedto the repair. Ofloxacin had no adverse effects on the articularcartilage in rats when treatment was initiated at 8 weeks ofage or later.