Mouse Sperm Association During Epididymal Transit

Abstract Head-to-head sperm association was described in some species as a normal phenomenon during epididyma transit (Phillips and Bedford, 1987). Recently, a new sperm head association (SHA) was characterized in the rat (Fornés & Burgos 1990; 1994). At this moment, the study of SHA was extended to mouse sperm. SHA is a type of cell-cell interaction clearly observed when an a drop of epididymal fluid, obtained by a puncture of epididymal duct, is placed in a culture medium (HMB media: Modified Ringers medium). This preparation can be observed under contrast phase microscope (optiphot-2, Nikkon) with or without fixative (2% paraformaldehyde and 2% glutaraldehyde in 0.01 M PBS buffer, pH 7,2). The mass of spermatozoa begin to move but not as a single sperm. They move as a clump of sperm and without fixative the sperm motility alone disaggregate the SHA.