title: Spontaneous Lung Lesions in Aging Laboratory Rabbits ( Oryctolagus cuniculus).
abstract: Spontaneous age-related lesions of laboratory rabbits are not well documented in the contemporary scientific literature. A retrospective study of diagnostic necropsies of 36 rabbits >2 years of age found a number of common lung lesions. Fibromuscular intimal hyperplasia affected medium and to a lesser extent large pulmonary arteries and was present to a variable extent in all 36 rabbits >2 years of age. The lesions were characterized by fragmentation and/or reduplication of the internal elastic lamina (IEL), proliferation of smoothelin+/alpha-smooth muscle actin (α-SMA)+/vimentin- smooth muscle cells and fewer smoothelin-/α-SMA+/vimentin+ myofibroblasts, and intimal deposition of collagen without thrombosis, embolism, or evidence of pulmonary hypertension. Pulmonary emphysema, present in 30/36 rabbits, was characterized by the loss of alveolar septa; most affected rabbits did not have clinical signs of respiratory disease. In 8/13 rabbits of the inbred EIII/JC audiogenic strain, we identified a unique syndrome of granulomatous pneumonia containing hyaline brown to gray, globular to ring-like acellular material that was Alcian blue and periodic acid-Schiff positive. The material was immunoreactive for surfactant protein-A and had the ultrastructural appearance of multilamellar vesicles, suggesting a genetic defect in surfactant metabolism. Additionally, we found small benign primary lung tumors (fibropapillomas, 5 rabbits) not previously described. Other findings included heterotopic bone (5 rabbits), subacute to chronic suppurative bronchopneumonia, pyogranulomatous pneumonia with plant material, and pulmonary artifacts from barbiturate euthanasia solution.
authors: 1 Department of Comparative Medicine, Penn State Hershey Medical Center, Hershey, PA, USA.|2 Department of Pathology, Penn State Hershey Medical Center, Hershey, PA, USA.
authors: T K
authors: TK
authors: Cooper
authors: 1 Department of Comparative Medicine, Penn State Hershey Medical Center, Hershey, PA, USA.
authors: J W
authors: JW
authors: Griffith
authors: 3 Department of Pediatrics, Penn State Hershey Medical Center Hershey, PA, USA.
authors: Z C
authors: ZC
authors: Chroneos
authors: 1 Department of Comparative Medicine, Penn State Hershey Medical Center, Hershey, PA, USA.
authors: J M
authors: JM
authors: Izer
authors: 1 Department of Comparative Medicine, Penn State Hershey Medical Center, Hershey, PA, USA.
authors: L B
authors: LB
authors: Willing
authors: 1 Department of Comparative Medicine, Penn State Hershey Medical Center, Hershey, PA, USA.
authors: X
authors: X
authors: Peng
mesh_terms: D000375:Aging / Q000473:pathology; D000818:Animals; D005260:Female; D008168:Lung / Q000473:pathology*; D008297:Male; D011014:Pneumonia / Q000473:pathology / Q000662:veterinary; D011651:Pulmonary Artery / Q000473:pathology; D011817:Rabbits / Q000033:anatomy & histology / Q000502:physiology*; D012189:Retrospective Studies
keywords: aging; background; emphysema; lung; neoplasia; pneumonia; pulmonary artery; rabbit; surfactant