Seminal Plasma Cytokines Are Predictive of the Outcome of Boar Sperm Preservation

Abstract

Background: Boar seminal plasma is rich in cytokines, which could influence the capability of spermatozoa to tolerate preservation.Objectives: To evaluate the involvement of boar seminal plasma cytokines in the changes experienced by boar spermatozoa during their storage, either in liquid or frozen state.Materials and Methods: In two separated experiments, semen samples from healthy and fertile boars were split in two aliquots, one centrifuged twice (1,500 ×g for 10 min) to harvest seminal plasma, whereas the other was either commercially extended (3 × 107 sperm/mL) and liquid-stored at 17°C during 144 h (n = 28, Experiment 1) or frozen-thawed using a standard 0.5 mL protocol (n = 27, Experiment 2). Sixteen cytokines were quantified using Luminex xMAP®. Sperm attributes (CASA-evaluated total and progressive motility; flow cytometry-evaluated sperm viability, production of intracellular H2O2 and O2•- and levels of lipid peroxidation in viable spermatozoa) were evaluated either at 0, 72, or 144 h of liquid storage (Experiment 1) or before freezing and at 30- and 150-min post-thawing (Experiment 2).Results: Multiple linear regression models, with Bayesian approach for variable selection, revealed that the anti-inflammatory TGF-β2, TGF-β3, IL-1Ra, and IL-4 and the pro-inflammatory IL-8 and IL-18, predicted changes in sperm motility for liquid-stored semen while the anti-inflammatory IFN-γ was included in the models predicting changes in all sperm attributes for cryopreserved semen.Conclusion: Specific boar seminal plasma cytokines would contribute to modulate the structural and metabolic changes shown by spermatozoa during preservation, either in liquid or frozen state.

Period of Boar Ejaculate Collection Contributes to the Yearly Intra-Male Variability of Seminal Plasma Cytokines

“…The first result of the present study verified the variability between males (inter-male) in the SP concentration of all measured cytokines, already known in pigs [19] and in males of other mammalian species such as humans [18]. Such inter-male variability opens up the possibility of using the SP concentration of some cytokines as a diagnostic tool for some male reproductive disorders [29][30][31], ejaculate parameters [16,32], and even to predict the ability of spermatozoa to withstand some biotechnological procedures, such as cryopreservation [33]. However, the results of the present study, demonstrating a substantially higher intra-male variability than inter-male variability, weaken the practical usefulness of SP-cytokine concentrations as a diagnostic tool.…”

Seminal Plasma Anti-Müllerian Hormone: A Potential AI-Boar Fertility Biomarker?

“…Similarly, variation in SP-AMH between individuals has also been evidenced in humans [14,19,20,36]. Inter-boar variability in other SP-proteins, including other members of the TGFβ-superfamily, has also been reported [8,9,11], and might have a genetic origin [37]. Indeed, AMH gene polymorphisms condition circulating serum AMH levels in men [38], so it is likely that the AMH concentration in SP is also genetically determined.…”

“…Another parameter that was assessed in Experiment 2 was the levels of sperm intracellular H 2 O 2 . Recently, the concentration of a different TGFβ-superfamily member, TGFβ-3, in boar SP has been shown to be related to the ability of sperm to modulate intracellular H 2 O 2 levels [11]. However, no differences were observed in sperm H 2 O 2 levels between samples with high or low SP-AMH concentration, which would suggest that the AMH does not participate in the maintenance of intracellular H 2 O 2 levels during storage at 17 • C.…”

“…This fluid interacts with sperm at the time of ejaculation and subsequently with the female genital tract [7], making it a good candidate for containing biomarkers of fertility. Indeed, it has been recently demonstrated that the concentration of certain SP proteins, such as transforming growth factor-β1 (TGF-β1), is related to liquid-stored and cryopreserved sperm quality and function, as well as to in vivo boar fertility outcomes [8][9][10][11]. In humans [12][13][14][15], there is evidence for another member of the TGF-β-superfamily, the anti-Müllerian hormone (AMH), playing a role in male fertility.…”

Sperm Proteome after Interaction with Reproductive Fluids in Porcine: From the Ejaculation to the Fertilization Site

“…The SP is involved in spermatozoa metabolism, survival, and transport within the female reproductive tract [ 15 ], which includes inhibiting the female immune response [ 16 ]. The uterus acts against spermatozoa by migrating polymorphonuclear (PMN) granulocytes [ 17 , 18 ] and this immune response may be modulated by SP, as it contains several cytokines interacting with the uterus epithelium, as previously shown in boar [ 19 , 20 ]. It has been shown in mice that SP contains SVS2 (seminal vesicle secretion 2), an SP protein involved in maintenance of the physiology of spermatozoa within the uterus [ 3 ].…”