SILICA WOOL FILTRATION (SIFT) ASSAY - A SIMPLE SYSTEM TO ESTIMATE THEPERCENTAGE OF ACROSOME-REACTED SPERM

Objective-To develop a simple assay using the silica wool filtration ( SIFT) procedure to estimate percentage of acrosome-reacted (AR) sperm. Setting-Private andrology laboratory. Materials and Methods-Capacitat ed sperm processed by the SIFT procedure to remove nonviable sperm and those with broken membrane were acrosome reacted by induction with a calcium ionophore. Following the acrosome reaction, the sample was pro cessed by the SIFT procedure. Sperm concentration and acrosomal status were also determined before and after the SIFT procedure. Results-The SIFT procedure prevented AR sperm from filtering (mean +/- SD; 22.2 /- 1.9 vs. 9.8 +/- 4.9%). The mean percent of sperm retained in the fi lter (SIFT assay: 61.8 +/- 21.5%) was significantly higher than the pe rcent of AR sperm estimated by a staining technique (26.4 +/- 7.3%), b ut they were significantly correlated (r = .34) with each other. The f iltration of capacitated sperm prior to induction of the acrosome reac tion eliminated, or at least minimized, the possibility of falsely inc reasing the percent of AR sperm estimated by the SIFT assay. The highe r estimate obtained by SIFT assay, therefore, suggests that it may be estimating sperm at various stages that are undergoing the acrosome re action. Conclusion-The findings suggest that the SIFT assay could be u sed to estimate the percentage of AR spermatozoa.