Comparison of the uterine inflammatory response to frozen-thawed sperm from high and low fertility bulls

Effect of different sperm populations on neutrophils extracellular traps (NETs) formation in cattle

In cattle, clinical and subclinical inflammation in the bovine female reproductive tract (FRT) significantly reduces fertility. PMN participate in this FRT-associated inflammation by eliminating pathogens by eliciting various defense mechanisms, with the release of neutrophil extracellular traps NETs) being the latest process discovered. Consistently, human-, bovine- and porcine-derived spermatozoa induce release of NETs in exposed PMN of the same species origin, and thereby decreasing sperm motility through NETs-mediated entrapment. The release of NETs in the presence of different sperm sub-populations is evaluated in this work. Cryopreserved bovine sperm were selected and different sperm populations were used: viable sperm, sperm with oxidative stress, capacitated sperm, and sperm with loss of viability. Isolated PMN of dairy cows were co-incubated with these sperm populations for 4 h. Neutrophil elastase (NE) and DNA were detected by fluorescence microscopy analysis. It was noted that exposed bovine PMN released NETs in the presence of sperm. Moreover, sperm-triggered NETosis resulted different phenotypes of NETs, i. e. spread NETs (sprNETs), diffused NETs (diffNETs) and aggregated NETs (aggNETs). Viable/motile spermatozoa induced a higher proportion of NETotic cells at 15, 60 and 120 min in comparison to controls. In conclusion, all bovine sperm populations in co-culture with PMN generated NETs extrusion while viable sperm activated NETotic cells to a greater extent. With this being an early event in the activation of bovine PMN.

Cryoprotectants-Free Vitrification and Conventional Freezing of Human Spermatozoa: A Comparative Transcript Profiling

Introduction: Spermatozoa cryopreservation is an important technique to preserve fertility for males. This study aimed at exploring the stability of epigenetics information in human spermatozoa, manipulated by two different technologies, freezing and vitrification. Methods: Spermatozoa samples were distributed into three groups: 1. Fresh spermatozoa (control group), 2. Frozen spermatozoa, 3. Vitrified spermatozoa. Epigenetic differences of fresh and cryopreserved spermatozoa were evaluated using high-throughput RNA sequencing. Results: Differentially expressed genes (DEGs) in frozen (1103 genes) and vitrified (333 genes) spermatozoa were evaluated. The bioinformatical analysis identified 8 and 15 significant pathways in groups of frozen and vitrified spermatozoa, respectively. The majority of these pathways are most relevant to immune and infectious diseases. The DEGs of the fertilization process are not detected during vitrification. The freezing process induces more down-regulation of genes and is relevant to apoptosis changes and immune response. Conclusion: Cryopreservation of human spermatozoa is an epigenetically safe method for male fertility preservation. Cryoprotectant-free vitrification can induce more minor biological changes in human spermatozoa, in comparison with conventional freezing.