• Citer

Evaluation of sperm capacitation as a parameter of male infertility diagnosis and impact of the cryopreservation process

par Pening, David ;Vegh, Grégory ;Leleux, Fabienne ;Delbaere, Anne ;Demeestere, Isabelle ;Lybaert, Pascale
Référence 16th Meeting of the Network of Young Researchers in Andrology(May 27-29, 2024: Brussels)
Publication Publié, 2024-05-27

Abstract de conférence

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Résumé :

Sperm cryopreservation plays a key role in Assisted Reproductive Technology, yet the technique may impair semen sample quality and its fertility potential post-thawing. Capacitation is defined as a physiological process through which sperm gain the ability to fertilize oocytes, involving changes in membrane potential (MP), intracellular pH (pHi) and intracellular calcium concentration. The endpoints of capacitation are hyperactivation and acrosomal exocytosis (AR). The aim of the study is to evaluate the impact of the freezing procedure on the capacitation ability of normospermic samples and their fertilization potential. Voltage-sensitive (DiSC3(5)) and pH-sensitive (BCECF-AM) dyes are used to measure the average MP and pHi, respectively, on sperm populations. Acrosomal exocytosis is evaluated using PNA -FITC staining of the acrosome on sperm smear as well as the quantification of the spontaneous and induced acrosome-reacted sperm. We compare two techniques (spectrofluorimetry versus flow cytometry) and two different capacitating media (Sperm Medium (SM) versus Human Tubal Fluid (HTF)) to measure MP and pHi in both fresh and frozen samples. A two-way repeated-measures ANOVA demonstrated that both techniques are comparable to measure the average MP. For fresh samples, an effect of the media on MP is observed (p=0.0016). The mean MP is more hyperpolarized for all fresh samples incubated in SM media. The spontaneous AR is significantly higher post-thawing (69.5%  2.1) compared to fresh samples (51.7%  4.6). No differences are found between fresh and frozen samples with regards to acrosome reaction induced by progesterone or calcium ionophore A23187. Subsequently, we extend the incubation of thawed samples in SM media up to 5h and found comparable average MP and pHi (t0 and t5). Finally, no significant correlation is found between mean MP and pHi and the fertilization rate by ICSI (r=-0.03, p=0.9). To summarize, the average MP of human sperm samples can be measured equally by spectrofluorimetry or flow cytometry. An impact of the capacitating media on the MP is observed in all fresh samples. The freezing procedure affects the endpoints of capacitation with an increase in the spontaneous AR. Further studies are needed to evaluate the capacitation process in the diagnosis of male infertility and ART.