No abstract

Cryopreservation is a vital procedure with widespread application for long-term storage of boar sperm (Holt, 2000). Since the 1950s, sperm (including boar, horse, and bull) were successfully cryopreserved (Curry, 2000; Polge, 1957); the quality of post-thawed semen has been improved. However, the poor sperm quality, including reduction of motility and viability, loss of mitochondrial function, and damage of DNA, is commonly observed after freezing-thawing, which results in low fertility (Amidi, Pazhohan, Shabani, Khodarahmian, & Nekoonam, 2016; Zribi et al., 2010). Specifically, compared with other animals (e.g., bull, goat), boar sperm is very sensitive to cryoinjury during cryopreservation (Didion, Braun, & Duggan, 2013; Hu et al., 2017), which greatly limits the application of its cryopreservation. Reactive oxygen species (ROS) are requirements for sperm capacitation, acrosome reaction, and binding to the zona pellucida at physiological concentrations (O'Flaherty, Beorlegui, & Beconi, 1999; Zribi et al., 2010). However, excessive ROS-induced oxidative stress has been suggested as a major contributing factor for cryodamage of frozen-thawed spermatozoa. It is commonly accepted that oxidative stress can damage the sperm cell membrane (Ford, 2004),

Phospholipase C (PLC) can participate in cell proliferation, differentiation and aging. However, whether it has a function in apoptosis in porcine primary granulosa cells is largely uncertain. The objective of this study was to examine the effects of PLC on apoptosis of porcine primary granulosa cells cultured in vitro. The mRNA expression of BAK, BAX and CASP3, were upregulated in the cells treated with U73122 (the PLC inhibitor). The abundance of BCL2 mRNA, was upregulated, while BAX and CASP3 mRNA expression was decreased after treatment with m-3M3FBS (the PLC activator). Both the early and late apoptosis rate were maximized with 0.5 μM U73122 for 4 h. The rate of early apoptosis was the highest at 4 h and the rate of late apoptosis was the highest at 12 h in the m-3M3FBS group. The protein abundance of PLCβ1, protein kinase C β (PKCβ), calmodulin-dependent protein kinaseII α (CAMKIIα) and calcineurinA (CalnA) were decreased by U73122, and CAMKIIα protein abundance was increased by m-3M3FBS. The mRNA expression of several downstream genes (CDC42, NFATc1, and NFκB) was upregulated by PLC. Our results demonstrated that apoptosis can be inhibited by altering PLC signaling in porcine primary granulosa cells cultured in vitro, and several calcium−sensitive targets and several downstream genes might take part in the processes.

SIRT2, the predominantly cytosolic sirtuin, plays important role in multiple biological processes, including metabolism, stress response, and aging. However, the function of SIRT2 in gap junction intercellular communications (GJICs) of cumulus-oocyte complexes (COCs) is not yet known. The purpose of the present study was to evaluate the effect and underlining mechanism of SIRT2 on GJICs in COCs. Here, we found that treatment with SIRT2 inhibitors (SirReal2 or TM) inhibited bovine oocyte nuclear maturation. Further analysis revealed that SIRT2 inactivation disturbed the GJICs of COCs during in vitro maturation. Correspondingly, both the Cx43 phosphorylation levels and MEK/MER signaling pathways were induced by SIRT2 inhibition. Importantly, SIRT2-mediated Cx43 phosphorylation was completely abolished by treatment with MEK1/2 inhibitor (Trametinib). Furthermore, treatment with SIRT2 inhibitors resulted in the high levels of MEK1/2 acetylation. Functionally,