Short Communication IXth International Conference on Boar Semen Preservation 2019

Relative GSTM3-abundance in fresh boar sperm is related to their cryotolerance (#1.2)

Marc Llavanera 1 , Ariadna Delgado-Bermúdez 1 , Sergi Bonet 1 , Yentel Mateo 1 , Beatriz Fernández-Fuertes 1 , Sandra Recuero 1 , Isabel Barranco 1 , Marc Yeste 1
  1. Biotechnology of Animal and Human Reproduction (TechnoSperm), Department of Biology, Institute of Food and Agricultural Technology, University of Girona, Girona, Spain

Cryopreservation is the most efficient method for long-term storage of mammalian gametes and is extensively used in assisted reproduction techniques (ART). However, cryoinjuries cause detrimental effects upon sperm function and survival. Furthermore, frozen-thawed sperm are known to be more damaged in pigs than in other species, and it has been reported that individual differences in the ability to withstand freeze-thawing between ejaculates exist. For this reason, boar ejaculates are classified as good freezability ejaculates (GFE) and poor freezability ejaculates (PFE). GSTM3 is a membrane-bound protein present in mammalian sperm and is involved in cell protection against oxidative stress and toxic chemicals. Recently, levels of GSTM3 have been related to fertility in both human and boar sperm. Against this background, this work sought to determine whether the relative levels of GSTM3 in fresh boar sperm are related to their resilience to withstand freeze-thawing protocols. With this purpose, 10 boar ejaculates were cryopreserved and classified as GFE or PFE. Sperm motility and viability were evaluated at 30 and 240 min post-thaw through CASA and flow cytometry. Six ejaculates were classified as GFE (%SYBR14+/PI- spermatozoa at 30 min post-thaw: 30.4% ± 2.6%) and four as PFE (%SYBR14+/PI- spermatozoa at 30 min post-thaw: 7.0% ± 1.8%). Relative GSTM3-content in fresh sperm was evaluated through immunoblotting. PFE showed higher relative levels of GSTM3 than GFE (1.1 ± 0.2 vs. 0.7 ± 0.1, P<0.05) in fresh sperm. Therefore, the differential content of GSTM3 in fresh sperm between GFE and PFE suggests that this protein could be used as a marker of boar sperm cryotolerance. However, further studies evaluating the localisation changes of this protein during freeze-thawing are required to elucidate the relationship between GSTM3 and boar sperm cryotolerance. This work was supported by Ministry of Science, Innovation and Universities, Spain (Grants: RYC-2014-15581 andAGL2017-88329-R).