Browsing by Subject "Phloretin"

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    Aquaglyceroporins but not orthodox aquaporins are involved in the cryotolerance of pig spermatozoa
    (2019-10-14) Delgado Bermúdez, Ariadna; Fernández Bastit, Leira; Recuero, Sandra; Mateo Otero, Yentel; Bonet, Sergi; Barranco Cascales, Isabel; Fernández Fuertes, Beatriz; Yeste, Marc; Medicina y Cirugía Animal
    Background: Aquaporins (AQPs) are a family of transmembrane water channels that includes orthodox AQPs, aquaglyceroporins (GLPs) and superAQPs. AQP3, AQP7, AQP9 and AQP11 have been identified in boar sperm, and they are crucial for sperm maturation and osmoregulation. Water exchange is an important event in cryopreservation, which is the most efficient method for long-term storage of sperm. However, the freeze-thaw process leads to sperm damage and a loss of fertilizing potential. Assuming that the quality of frozen-thawed sperm partially depends on the regulation of osmolality variations during this process, AQPs might play a crucial role in boar semen freezability. In this context, the aim of this study was to unravel the functional relevance of the different groups of AQPs for boar sperm cryotolerance through three different inhibitors. Results: Inhibition of different groups of AQPs was found to have different effects on boar sperm cryotolerance. Whereas the use of 1,3-propanediol (PDO), an inhibitor of orthodox AQPs and GLPs, decreased total motility (P < 0.05), it increased post-thaw sperm viability, lowered membrane lipid disorder and increased mitochondrial membrane potential (MMP) (P < 0.05). When acetazolamide (AC) was used as an inhibitor of orthodox AQPs, the effects on post-thaw sperm quality were restricted to a mild increase in MMP in the presence of the intermediate concentration at 30 min post-thaw and an increase in superoxide levels (P < 0.05). Finally, the addition of phloretin (PHL), a GLP inhibitor, had detrimental effects on post-thaw total and progressive sperm motilities, viability and lipid membrane disorder (P < 0.05). Conclusions: The effects of the different inhibitors suggest that GLPs rather than orthodox AQPs are relevant for boar sperm freezability. Moreover, the positive effect of PDO on sperm quality suggests a cryoprotective role for this molecule.
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    Open Access
    Effect of AQP inhibition on boar sperm cryotolerance depends on the intrinsic freezability of the ejaculate
    (MDPI, 2019-12-11) Delgado Bermúdez, Ariadna; LLavanera, Marc; Recuero, Sandra; Mateo Otero, Yentel; Bonet, Sergi; Barranco Cascales, Isabel; Fernández-Fuertes, Beatriz; Yeste, Marc; Medicina y Cirugía Animal; Facultad de Veterinaria
    Aquaporins (AQPs) are transmembrane channels with permeability to water and small solutes that can be classified according to their structure and permeability into orthodox AQPs, aquaglyceroporins (GLPs), and superAQPs. In boar spermatozoa, AQPs are related to osmoregulation and play a critical role in maturation and motility activation. In addition, their levels differ between ejaculates with good and poor cryotolerance (GFE and PFE, respectively). The aim of this work was to elucidate whether the involvement of AQPs in the sperm response to cryopreservation relies on the intrinsic freezability of the ejaculate. With this purpose, two different molecules: phloretin (PHL) and 1,3-propanediol (PDO), were used to inhibit sperm AQPs in GFE and PFE. Boar sperm samples were treated with three different concentrations of each inhibitor prior to cryopreservation, and sperm quality and functionality parameters were evaluated in fresh samples and after 30 and 240 min of thawing. Ejaculates were classified as GFE or PFE, according to their post-thaw sperm viability and motility. While the presence of PHL caused a decrease in sperm quality and function compared to the control, samples treated with PDO exhibited better quality and function parameters than the control. In addition, the effects of both inhibitors were more apparent in GFE than in PFE. In conclusion, AQP inhibition has more notable consequences in GFE than in PFE, which can be related to the difference in relative levels of AQPs between these two groups of samples.