IS SPERMATOZOAN ACROSIN A PREDICTOR OF FERTILIZATION AND EMBRYO QUALITY IN THE HUMAN

Objective: To investigate whether acrosin is a more reliable criterion than conventional parameters for assessing semen samples. Design: Tot al acrosin was estimated biochemically in semen samples obtained for r outine screening for infertility and for IVF-ET procedures. Setting: A ssisted Conception Unit, St. James's University Hospital, Leeds, Unite d Kingdom. Patients: Four hundred sixty-three couples being investigat ed for causes of infertility, and 132 couples undergoing IVF-ET for an y indication except antisperm antibodies between 1990 and 1991 were in cluded in the study. Interventions: Semen samples were collected as pa rt of routine investigation. Samples from men with consistently high v iscosity were collected in alpha-chymotrypsin. Main Outcome Measures: Total spermatozoan acrosin in motile spermatozoa and motile spermatozo an density in couples being assessed for IVF-ET and fertilization and embryo quality in those receiving treatment are considered. Results: T otal acrosin levels were less variable (within subject) than either to tal or motile spermatozoan concentration at ejaculation. Although seve rely oligozoospermic ejaculates had the lowest levels of total acrosin , overall, there was no significant correlation of spermatozoan concen tration between total acrosin levels and percentage fertilization. Con clusions: Total spermatozoan acrosin activity correlates positively wi th fertilization rates but not with spermatozoan count. Motile spermat ozoan density for insemination may be adjusted to achieve >7.5 muIU ac rosin per oocyte, without compromising fertilization or further embryo development to blastocysts in vitro.