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

Immunopathological findings in a cat with auricular chondritis

At clinical examination, a 5-year-old male domestic short-haired cat exhibited painful swelling and erythema of the pinnae of both ears. Microscopically, the lesions on both pinnae were composed of diffuse granulomatous chondritis with degeneration and necrosis of the pinnal cartilage. Numerous mast cells were also observed within and surrounding the inflammatory lesion. Immunohistochemistry showed a mixed inflammatory infiltrate characterised by the predominance of macrophages (CD68+, MAC 387+ and Lysozyme+), T lymphocytes (CD3+), some B lymphocytes (CD79α+) and neutrophils. Immunopathological characterisation of the lesion showed a granulomatous inflammation profile and suggests that the morphological changes and immunopathogenesis of auricular chondritis in cats presents a similarity with relapsing polychondritis in humans.

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

Although it has been shown that auricular chondritis in rats is caused by the use of metal identification ear tags, the pathogenesis remains unclear. Based on the hypothesis that the auricular chondritis is caused by metal ions released from metal identification ear tags, we investigated the pathogenesis in male C57BL/6 mice tagged with metal identification ear tags. Twenty-six weeks after the attachment of the ear tags, visible increases in the thickness of the auricle were observed, and the concentrations of copper and iron in the tagged ears were significantly increased ( P <.05) in the tagged ears compared with the untagged ears. There was up-regulation of metallothionein (MT)-I and MT-II mRNA in the tagged ears, and this was confirmed by immunohistologic staining of the destroyed cartilage. Histopathologically, there were observed severe chondritis with extensive granulomatous inflammation, newly formed cartilage nodules, and osseous metaplasia accompanied by cellular infiltrates, such as CD4 T lymphocyte, macrophages, neutrophils, and mast cells, and expression of Th1 cytokines, such as interferon-gamma, tumor necrosis factor-alpha, and interleukin-2 in the tagged ear. Based on these results, we concluded that the release of copper and iron ions from the metal ear tags played a major role in the onset of auricular chondritis. Subsequent cellular interactions, such as CD4 T cells, macrophages, fibroblasts, and mast cells, mediated by cytokines, such as tumor necrosis factor-alpha and interferon-gamma, caused an autoimmune response that may have led to the progression of auricular chondritis as an autoimmune disease.

A Case of Bilateral Auricular Chondritis in a Heifer

Auricular chondritis is an extremely rare condition in cattle and other domestic animals. A 13-month-old Jersey heifer was presented with cutaneous papillomatosis and bilaterally droopy ears. Histopathology revealed bilateral auricular chondritis characterized by lymphoplasmacytic infiltrate and extensive destruction and fibrosis of the auricular cartilage.

Auricular chondropathy in rats at a contract research toxicology laboratory

ABSTRACT The veterinary staff at WIL Research Laboratories, LLC, was asked to assess and characterize a condition of swollen and reddened ears that had been observed in some of the rats in our facility. When all of the Crl:CD(SD) rats in the facility were examined in August of 2004, August of 2005, and February of 2007, the incidences were 0.25%, 0.18%, and 0.19%, respectively. The overall incidence was 0.21%, with a total of 51 of 24677 animals affected. Only bilaterally affected animals were considered positive. Incidence was strongly correlated with the presence of an ear tag. All but one of the affected animals had an ear tag present. Severe auricular chondropathy was diagnosed on microscopic exam.