Effect of cryopreservation on human sperm messenger RNAs crucial for fertilization and early embryo development

During recent years, several studies have pointed out the importance of key paternal transcripts in early embryo development. Sperm cryopreservation is commonly applied in assisted reproductive technologies (ARTs) and it is important to know if it produces any relevant effect at this level. In this study, using normozoospermic donors, we present a candidate transcript approach in which we quantify the presence of sperm mRNAs considered as markers for male fertility and pregnancy success. Analyses were done using quantitative PCR. Our results demonstrated that the used cryopreservation protocol, which is routinely employed in clinical practice, alter transcripts considered as spermatozoa quality markers and markers for pregnancy success. Most of the studied transcripts considered as male quality markers (PRM1, PRM2, and PEG1/MEST) and one of studied mRNAs reported as markers of pregnancy success (ADD1) were reduced after cryopreservation. In order to check if vitrification protocols could reduce this alteration, another assay was carried out analyzing those transcripts with higher differences in the first study (PRM1 and PRM2). The results showed the same tendency. Although maternal mRNAs can compensate these deficiencies, these results could make advisable the optimization of freezing/thawing procedures.