Separation of human semen on percoll gradients: effect on percentage of motile and morphologically normal sperm and proportion of acrosome reacted sperm

Objectives - To examine whether sperm motility and morphology correlate with ability to undergo the acrosome reaction in vitro. Methods - Sixty-one seminal specimens were separated on a discontinuous Percoll gradient (70%, 40%). Percentages of motile and morphologically normal sperm, their motility grade, and percentages of acrosome-reacted sperm before and following acrosome reaction inducing treatment were estimated. Results- Percentage of motile sperm from normozoospermic specimens increased from whole semen (47.6 ± 5.6) to sediments (59.6 ± 13.0). Motility grade exhibited a similar trend (2.1 ± 0.5 and 3.6 ± 0.5-scale of 1-4). Percentage of morphologically normal sperm increased from semen (27.3 ± 10.9) to sediment (53.8 ± 14.8). All differences were statistically significant, (P < 0.00). In abnormal semen the motility grade and percentage of morphologically normal sperm also increased from semen to sediment (1.9 ± 0.4 to 3.2 ± 0.8 and 17.7 ± 7.8 to 37.1 ± 15.4 respectively, (P < 0.001). Percentages of motile sperm were similar. In normozoospermic sediments, both non-treated or treated to induce the acrosome reaction, proportions of acrosome-reacted sperm were significantly higher than in semen (18.3 ± 6.9% and 20.0 ± 6.5% vs. 6.8 ± 4.2% respectively, P < 0.001). A similar trend was obtained using abnormal aliquots; however, the acrosome-reacted sperm accounted for only 9.0 ± 5.1% and 10.8 ± 4.3% versus 5.4 ± 2.8% (P < 0.025). Conclusions - Morphology and motility of sperm were correlated with the proportion of acrosome-reacted sperm.