Improvement of Human Sperm Vacuolization and DNA Fragmentation Co-Cultured with Adipose-Derived Mesenchymal Stem Cell Secretome: In Vitro Effect

Background and Objectives

Oxidative stress (OS) is known to be an important factor of male infertility. Adipose-derived mesenchymal stem cells (AD-MSCs) are known to have immune-modulatory and anti-oxidant effects through their secretions, hence raising the idea of their potential benefit to improve sperm parameters. This study aims at investigating the effect of AD-MSCs conditioned medium (CM) on human sperm parameters in the presence and absence of H₂O₂-induced OS.

Methods and Results

Sperm samples were collected from 30 healthy men and divided into two groups: non-stressed and H₂O₂-stressed. Isolated AD-MSCs from healthy donors undergoing liposuction were cultured and CM was collected at 24, 48 and 72 h. Both sperm groups were cultured with CM and a time course was performed followed by an evaluation of sperm parameters. The incubation of non-stressed and stressed sperm samples with AD-MSCs-CM for 24 h was found to have the optimum impact on sperm vacuolization, DNA fragmentation and OS levels in comparison to other incubation timings, while preserving motility, viability and morphology of cells. Incubation with CM improved all sperm parameters except morphology in comparison to the non-treated group, with the best effect noted with CM collected at 24 h rather than 48 or 72 h for sperm vacuolization and DNA fragmentation. When compared to fresh semen parameters (T0), samples cultured with CM 24 h showed a significant decrease in sperm vacuolization and DNA fragmentation while keeping other parameters stable.

Conclusions

AD-MSCSs-CM improves sperm quality, and hence can be used in treating infertility and subsequently enhancing IVF outcomes.

Cryopreservation media differentially affect sperm motility, morphology and DNA integrity

INTRODUCTION

Human sperm freezing is very widely used for male fertility preservation. This procedure consists in adding cryoprotectants to the spermatozoa followed by cooling and storing the spermatozoa at a subzero temperature. Many standardized cryopreservation media are available on the market. However, these media differ in their chemical composition and there are no sufficient data to optimize their classification. Therefore, the aim of this study was to compare five commercially available sperm cryopreservation media, which have not been compared together, in terms of motility, morphology and DNA integrity.

MATERIALS AND METHODS

One-hundred semen samples were obtained from 10 fertile participants and 90 infertile men. Each sample was evaluated before freezing for motility, morphology and DNA fragmentation index (DFI). Then, it was equally divided into five aliquots. Each aliquot was cryopreserved using one of the five media (A, B, C, D, and E). The same parameters were re-evaluated after the addition of the cryopreservation media in the fertile group, and after sperm thawing in fertile and infertile groups.

RESULTS

The results showed that the five selected cryopreservation media had negative effects on sperm motility and morphology per se. In the infertile group, the cryosurvival factor was significantly lower in cryomedium A when compared to the four other media (p < 0.001). In addition, a significantly higher percentage of sperm with coiled tail was detected in cryomedium E compared to cryomedium A (p < 0.05) and to cryomedium B (p < 0.001) after thawing, in the infertile group. Furthermore, the sperm DFI was significantly higher in cryomedia A (p < 0.001), B (p < 0.001), C (p < 0.01), D (p < 0.01) and E (p < 0.05) compared to that of the fresh semen derived from infertile participants.

CONCLUSION

This study indicates that the recovery rate of competent spermatozoa, after cryopreservation, is still critical in infertile men. Therefore, frozen semen sample should be used only when necessary.