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

Abstract

SummaryGross and histopathological features of auricular chondritis in young Crj:CD(SD)IGS rats were examined. Although the rats were identi ed with metallic ear tags on the right pinnae, auricular chondritis was also observed on the contralateral (left) ear in some animals. Histopathologically, the lesions were characterized by granulomatous in ammation with destruction of the normal cartilaginous plate, formation of new cartilaginous nodules and osseous metaplasia. Proliferative cell nuclear antigen (PCNA) positive cells were present predominantly in chondrocytes found in the centre of the newly-formed cartilaginous nodules. The results suggest that the newly-formed cartilaginous nodules were due to interstitial proliferation of chondrocytes.

Immunopathological findings in a cat with auricular chondritis

“…Histologically, auricular cartilage necrosis/degeneration and fibroplasia, surrounded by inflammatory infiltrate, are the hallmarks of the disease in feline species (Delmage and Kelly, 2001;Gerber et al, 2002;Baba et al, 2009). The regenerative nodules of cartilage observed here were previously reported in a heifer, in mice with experimentally induced AC (Kitagaki et al, 2003;Kitagaki and Hirota, 2007;Adissu et al, 2014), and in a cat with RP (Baba et al, 2009). The pinnal cartilage injury, in addition to releasing proinflammatory cytokines (Kitagaki and Hirota, 2007), possibly triggered the regenerative response of the chondrocytes.…”

A Case of Bilateral Auricular Chondritis in a Heifer

“…A similar condition has been described in laboratory rodents, notably in rats, a species that has been proposed as a model for relapsing polychondritis in human beings. In rats, it has been reported as an idiopathic/spontaneous [5,6] or as experimental type II collagen-induced condition [4]. Interestingly, development of bilateral auricular chondritis has been reported secondary to unilateral application of metallic ear tags in rats [6] and mice [7].…”

“…In human beings, it manifests as part of relapsing polychondritis complex, a rare systemic autoimmune disease characterized by episodic destructive inflammation of cartilaginous tissues throughout the body especially those of the ear, nose, joints, and respiratory tract [1][2][3]. In animals, auricular chondritis has been reported in rats [4][5][6], mice [2,7], cats [8][9][10], and a horse [11]. It is extremely rare in cattle and, to the authors' knowledge, there is only a single case report involving two heifers [12].…”

Rodent and Rabbit Welfare in the Research Environment

“…When possible, sedatives or local analgesics, such as lidocaine-containing creams or local anesthetic sprays, should be given or applied a priori to minimize pain. When ear tags are used, nylon ear tags are preferable over metal, because metal tags may induce auricular chondritis with resulting inflammation and pain, in multiple species (Kitagaki et al, 2003;Kitagaki and Shibuya, 2004;Kitagaki and Hirota, 2007). For some procedures, such as toe clipping or ear punching of young rodent pups, the actual procedure has been shown to be no more stressful to a pup than restraint stress, provided that the procedures are performed rapidly and skillfully (Castelhano-Carlos et al, 2010;Schaefer et al, 2010).…”