Polycystic kidney and liver disease in Springbok: I. Morphology of the lesions.

Spontaneous polycystic kidney and liver disease in an inbred herd of Springbok (Antidorcas marsupialis) was studied by light microscopy, transmission electron microscopy, and microdissection. Springbok are a small species of gazelle of the family Bovidae native to South Africa. Since 1976, 18% of all live calves born have had nephromegaly and died within 2 weeks of birth. Examination of kidney and liver from ten calves which had died or were sacrifices since 1978 revealed bilateral, symmetrical nephromegaly due to moderate to marked focal dilatation of tubules predominately in the outer zone of the medulla. Microdissection of renal tissue from three affected calves indicated polycystic kidneys had cysts in all of the bends of Henle's loops, over half of the ascending limbs, and about one fourth of the collecting ducts. All of these calves had proliferation and cystic dilatation of bile ducts in most hepatic portal areas. The bile ducts were irregularly dilated and confluent with only a slight increase in periductular connective tissue. Ultrastructural studies revealed no consistent changes in the basement membranes of either the renal or hepatic cysts. This disease has several features similar to the autosomal recessive form of polycystic kidney disease in man and may prove a useful animal model.