Auricular Chondritis, Rat

Auricular Chondritis Caused by Metal Ear Tagging in C57BL/6 Mice

“…The clinical and histopathologic features of the chronic inflammation observed in mice with metal ear tags resembled those reported for induced or spontaneous auricular changes in rats. 4,20 This spontaneous auricular disease has not been described in other laboratory animal species, although inflammation as an extension of dermatitis may involve the auricular cartilage. 4 Although we observed bilateral (tagged and untagged) inflammatory nodular thickening of the ear pinnae in aging male C57BL/6 mice (approximately 60 weeks after tagging) in preliminary study, lesions were more marked in ears with metal ear tags (unpublished data), suggesting auricular chondritis may be induced not only in the rat but also in mice.…”

“…4,20 This spontaneous auricular disease has not been described in other laboratory animal species, although inflammation as an extension of dermatitis may involve the auricular cartilage. 4 Although we observed bilateral (tagged and untagged) inflammatory nodular thickening of the ear pinnae in aging male C57BL/6 mice (approximately 60 weeks after tagging) in preliminary study, lesions were more marked in ears with metal ear tags (unpublished data), suggesting auricular chondritis may be induced not only in the rat but also in mice. Ear thickening induced by traumatic insult at the time of tag insertion to the auricular cartilage was transitory and eventually healed without complications.…”

“…1-3), 5 for metal content and cytokine measurement (case Nos. [4][5][6][7][8], and 5 for immunohistochemistry (case Nos. 9-13).…”

Auricular chondritis in young ear-tagged Crj:CD(SD)IGS rats

“…The majority consisted of focal or multifocal granulomatous in ammation with destruction of the normal cartilaginous plate, formation of brochondrous or chondrous nodules and osseous metaplasia or sometimes a combination of these lesions (Chiu 1991). The sparse amount of elastic bres and the presence of abundant proteoglycan matrix indicate that the newlyformed cartilaginous nodules display structural characteristics of hyaline cartilage rather than elastic cartilage found in normal ear pinnae (Bradamante et al 1991).…”

“…Similar lesions however, have been experimentally induced in type II collagen immunized rats (Cremer et al 1981, McCune et al 1982) and mice (Bradley et al 1998, Fujiyoshi et al 1997, suggesting that immunological function may be related to the pathogenesis (Meingassner 1991). Auricular chondritis in rats bears some resemblance to relapsing polychondritis in humans, wherein the systemic manifestation of the disease also affects the auricles bilaterally (Chiu 1991 …”