Sperm vacuoles are linked to capacitation and acrosomal status

STUDY QUESTION Is the presence of nuclear vacuoles really a negative parameter? SUMMARY ANSWER As sperm vacuoles are associated with acrosomal and capacitation status, they appear to be a reflection of normal sperm physiology. WHAT IS KNOWN ALREADY The selection of sperm under a high magnification has been proposed as a strategy to increase the success rates of ICSI, through a better selection of sperm for injection. The presence of vacuoles on the sperm head is said to be a negative parameter. STUDY DESIGN, SIZE, DURATION We incubated processed sperm for 90 min with two strong inducers of acrosome reaction (AR), i.e. hyaluronic acid (HA) and follicular fluid (FF) and studied the evolution of nuclear vacuoles, sperm morphology and chromatin compaction. PARTICIPANTS/MATERIALS, SETTING, METHODS We tested the effect of incubating sperm samples with HA and FF for 90 min at 37°C on nuclear vacuoles. MAIN RESULTS AND THE ROLE OF CHANCE Both HA and FF strongly induce AR after 90 min, without significantly modifying sperm nuclear condensation and morphology (Bartoov's criteria). We simultaneously observed a highly significant decrease in the presence of vacuoles. LIMITATIONS, REASONS FOR CAUTION This is a descriptive study based on in vitro manipulations. WIDER IMPLICATIONS OF THE FINDINGS Although intracytoplasmic morphologically selected sperm injection may be of benefit for couples with specific treatment indications, the results of this study make it difficult to justify its large-scale application. STUDY FUNDING/COMPETING INTEREST(S) Funding was granted by Laboratoire d'Eylau, Unilabs.