1994 Volume 7 Issue 3 Pages 329-343
A variety of spontaneous lesions found histologically in control Beagle dogs (males: 91, famales; 97) used in toxicity studies that were conducted at the Biosafety Research Center, Foods, Drugs and Pesticides during a 10 year period, are described. All animals were exsanguinated by incision of the axillary artery under sodium pentobarbital anesthesia at the end of each study.
Neoplastic lesions included fibrosarcoma of the heart in a female dog at approximately 27 weeks of age (1.0%) and hemangioendothelioma of the spleen in a male dog, also at approximately 27 weeks of age (1.1%).
The most common non-neoplastic changes in both male and famale dogs were deposits of amorphous masses at the renal papilla (males; 68.1%, females ; 80.4%) and fetal glomerulus in the kidney (males; 53.8%, females; 50.5%). Fatty changes in the renal tubular epithelium of female dogs occurred at an incidence of greater than 50%. Pigment deposition in the spleen, guranulation of the liver, atrophy in the thymus, C-cell hyperplasia of the thyroid gland, and pituitary cysts in male and female dogs were evident at an incidence of greater than 10%. In addition, multinucleated giant cells in the testes, eosinophilic bodies in the renal tubular epithelium in males, cellular infiltration of the parotid gland, and deposits of calcium in the spinal cord of females were seen at incidences of greater than 10%. Atrophy of the thymus and C-cell hyperplasia of the thyroid increased with age. Fetal glomerulus of kidney decreased with age.
Other rare, but interesting lesions included: ectopic stomach tissue in the ileum, ductro-insular proliferation of the pancreas, deposits of calcium at the beginning portion of the aorta and in the spinal cord, and hemangiectasis at the atrioventriclar valve of the heart.
