Sperm association in the rat epididymis.

Abstract

During dissolution of drops obtained by puncture of rat epididymis in distal caput, mid corpus, proximal and distal cauda we observed in the last two regions the appearance of a new sperm association which we call rosette and the formation in the same two regions of dense clusters of non-motile degenerating spermatozoa already described in the rat vas deferens. Rosettes become organized in the proximal cauda by head to head sperm contact through a filamentous PAS positive material. By video microscopy was observed the dilution of a dense drop of cauda epididymal content in a balanced salt solution at 36 degrees C. In less than 3 min, rosettes become dispersed into single sperm with a display of intense motility which starts immediately after dilution. A glycoprotein with cohesive properties secreted by the epididymal epithelium is postulated as the factor promoting rosette formation. We confirm that dense clusters correspond to degenerating spermatozoa and describe its first appearance in the epididymal proximal cauda with increase in number toward vas deferens.