Species: Rat Strain/breeder: Wistar (Janvier, 53940 Le Genest St. Isle, France) Sex: Male Age: 8 - 10 weeks Study type: Palatability Treatment: 6 Weeks oral (feed admixture) Animal status: Scheduled sacrifice, termination of study Clinical findings: None Organ(s): Testis, epididymidis, efferent ducts Macroscopic finding(s): Right testis: flaccid and decreased in size Staining: H&E

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Abstract

S. HALM and M.M. RUF

Abbott GmbH & Co. KG, Toxicology, Knollstrasse 50, 67008 Ludwigshafen, Germany

Key words: testicular changes, epididymal changes, rat

The testes of Wistar rats treated orally with a test compound in the diet for 6 weeks revealed a diffuse testicular tubular atrophy associated with epididymal aspermia and granulomatous inflammation, sperm stasis and luminal occlusion in the efferent ducts. In addition, recanalisation of obviously blind ending duct epithelium was observed around the occluded ductules. The occlusion of efferent ducts blocked passage of sperm from the rete testis to the epididymis. Different pathogenetic pathways were discussed including the disruption of fluid reabsorption (increased or decreased reabsorption and/or secretion) resulting in altered fluid components and subsequent sperm stasis, or an effect on contractility. The changes in the efferent ducts are considered to represent the primary lesion induced by the test compound and are proposed to cause testicular atrophy and epididymal aspermia, resulting in infertility (HESS RA, NAKAI M (2000), Histol Histopathol 15: 207 - 224).