Relationship between human sperm morphology and acrosomal function

Purpose: In this study, we investigated the relationship between functionality of the acrosome and sperm morphology. Methods: Acrosome reaction (AR) was separately determined in live and dead sperm and in those with normal, small, and large sized acrosomes by means of the triple stain. Morphology was analyzed according to strict criteria after Papanicolaou stain. Results: AR and morphology correlated regarding detection of large and small sized acrosomes, but not for normal sized acrosomes. Spontaneous AR was significantly influenced by acrosomal size. Sperm with large (11.4%) and normal (9.2%) acrosomes exhibited a significantly higher percentage of life spontaneously acrosome-reacted sperm than those with small acrosomes (4.5%). Sperm with small acrosomes were associated with a higher percentage of cell death. Conclusion: The results indicate that sperm with small acrosomes are more susceptible to cell death and nonphysiological acrosomal loss. Acrosome size reflects the physiological capability of sperm function and therefore male fertility potential.