Glass wool filtration leads to a higher percentage of spermatozoa with intact acrosomes: an ultrastructural analysis

We investigated the possibility of ultrastructural damage to human spermato zoa induced by different sperm preparation techniques. Ejaculates from 20 n ormozoospermic men were divided into equal aliquots and processed by glass wool filtration, Percoll density gradient centrifugation, and a simple two- step centrifugation procedure which served as a control. The evaluation of 60 spermatozoa from each of 20 test subjects (in all, n = 1200) ensured tha t a sufficiently large number of spermatozoa were investigated. Ultrastruct ural damage was assessed by scanning electron microscopy, We investigated t he state of the acrosome after sperm preparation and measured the percentag e of intact spermatozoal structures compared with that of the control. Comp ared with Percoll density gradient centrifugation, glass wool filtration yi elded a significantly increased proportion of intact acrosomes, However, bo th preparations gave significantly better results than the control. In conc lusion, both glass wool filtration and Percoll centrifugation are efficient techniques for the accumulation of spermatozoa with intact acrosomes, Beca use of the significantly higher percentage of intact acrosomes, glass wool filtration appears to be the more appropriate method. The significance of t he conspicuous bending of sperm tails after Percoll centrifugation is not y et known.