EFFECTS OF ISCHEMIA ON THE CAPUT EPIDIDYMIS AND ITS RELATIONSHIP TO HIGHER EPIDIDYMAL OBSTRUCTION - A QUALITATIVE STUDY IN THE RAM

The objective of this study was to determine if localized ischaemia of the caput epididymis in the ram causes morphological changes similar to those characteristic of higher epididymal obstruction in humans. Th is was tested by performing unilateral occlusion of the superior epidi dymal artery in 10 rams. At the end of 4 (n=5) or 28 weeks (n=4), rams were castrated and the testes and epididymides were weighed. Analysis of histological sections at the light microscope level provided quant itative data on lumen diameter and epithelial cell height of the effer ent ducts. Qualitative analysis and specific histochemical stains for identification of lipofuscin pigment provided further information on t issue changes. Electron microscopy was performed on the efferent ducts to assess ultrastructural changes. The results revealed that localize d ischaemia of the proximal epididymis caused a dramatic change in tub ule calibre of the efferent ducts and initial segment resulting in obs truction of the distal lumina. These changes were more severe followin g 28 weeks of arterial occlusion. The epithelial cells of the proximal region showed an increase in the number of lysosomes and they became active in phagocytosis of spermatozoa. Lipofuscin pigment accumulated within the epithelial cells and also in macrophage-like cells that had invaded the lumina, interstitium and intra-epithelial regions of the ducts. On the basis of these observations we conclude that the tissue changes which occur in the ram epididymis as a result of localized isc haemia show a striking similarity to those seen in men exhibiting high er epididymal obstruction. This suggests the possible implication of v ascular disorders in the aetiology of obstructive azoospermia in men.