Comparative characteristics of spermatozoa harvested and cryopreserved in culture and cryoprotectant media with or without donor serum proteins.

The objectives of this study is to evaluate the efficacy of protein-free media in the preparation, holding and crypreservation of spermatazoa for use in ART. Normozoospermic semen samples (N=71) were used to compare the effects of media on the survival and quality of spermatozoa when washed and cultured with different media with and without added proteins at 4°C, 15°C, 22°C and 37°C for 0, 4-7 and 24h. Survival and quality of spermatozoa were assessed after freeze-thaw with synthetic cryoprotectant with and without proteins. Ethics/IRB approval was obtained (Ref. 1073.52). Spermatozoa parameters were similar in all media after washing and culture for 24h. Post-thaw survival and quality of spermatozoa was not significantly different 24h after thawing of samples frozen in all cryoprotectant medium. In conclusion synthetic protein-free culture and cryoprotectant media are equal in efficacy to protein-containing media in culture and cryopreservation of spermatozoa . Use of these synthetic media are anticipated to significantly reduce the risk, potentially associated with conventional protein-containing media, of transmission of disease and possibly harmful undeclared proteins to the patient, baby and the healtcare worker. Synthetic media also ensure consistency of quality between batches of media.

Impact of elemental iron on human spermatozoa and mouse embryonic development in a defined synthetic culture medium.

There is a paucity of studies on effect of iron in embryo culture procedures. This study aims to ascertain the optimal, tolerance and toxic levels of iron in a protein-free embryo culture medium (PFM) to determine the effect of iron on embryonic development. The application of PFM in assisted reproductive technologies (ART) is intended to eliminate disease transmission and improve ART treatment outcome. The optimal, tolerance and toxic levels of iron on human spermatozoa and mouse embryos were determined by challenging them with different levels of iron (ferric iron; Fe+3). Human normozoospermic semen samples (n=24) and days 1-4 Quakenbush Special (Qs) mouse embryos (n=1160) were incubated in PFM supplemented with different concentrations of Fe+3 over different periods of time. 2.0µg/mL (35.8µM) of Fe+3 was the optimal level of Fe+3 for human spermatozoa with a tolerance range of 0.5-2µg/mL; whereas a level of 0.11µg/mL (2µM) of Fe+3 was the optimum for day 2 embryos. Levels of ferric iron at 0.11 to 2.8µg/mL appear to enhance spermatozoa motility, preserve its DNA integrity and possibly increase percentage of blastocysts developed but levels of ferric iron >16µg/mL is hazardous for both spermatozoa and embryos. In spite of beneficial effects of iron it is premature to recommend its supplementation in embryo culture media because of the known deleterious nature of iron and the paucity of toxicological data. Toxicological studies must be performed following which it can be decided whether it is safe to consider iron as a supplement in human embryo and spermatozoa culture media.