Bisphenol A (BPA), an endocrine-disrupting chemical, has received tremendous attention in the past few decades because of its detrimental health effects. Growing evidence supports that BPA is capable to alter the reproductive performance of the exposed individual. In spermatozoa, it has been reported that BPA increased oxidative stress by the overproduction of reactive oxygen species (ROS), subsequently affects the sperm function, biochemical properties, and fertility. Since antioxidants minimize cellular oxidative stress, therefore may have protective effects against BPA-induced stress. In the present study, we incubated mice spermatozoa for 6 h in a condition that support in vitro fertilization. The sperm incubation media was additionally supplemented with either BPA or BPA together with antioxidants, such as glutathione, vitamin C, and vitamin E. Our results showed that antioxidant significantly decreased the production of ROS that subsequently supports motility and acrosomal integrity of BPA-exposed spermatozoa. Particularly, glutathione and vitamin E inhibit protein kinase-A dependent phosphorylation of sperm proteins subsequently prevented precocious acrosome reaction. In addition, both antioxidants were found to restore fertilization and early embryo development potentiality of BPA-exposed spermatozoa. Therefore, we conclude that antioxidants minimize oxidative stress in spermatozoa in a BPA containing micro-environment, thus avoiding BPA-mediated harmful consequences. The current finding has both theoretical and clinical significance for developing potential remedies of the BPA toxicity.

The ability of conventional semen analysis to predict male fertility is questionable. Since the prediction of male fertility is extremely of importance for the artificial insemination and profitable farm managements in animals, the development of highly sensitive biomarker of male fertility is a prime concern. Porcine Seminal Protein I (PSP-I) and Porcine Seminal Protein II (PSP-II) have been known that they are related with motility, and viability of spermatozoa. Thus, we investigated PSP-I and PSP-II level in boar spermatozoa to predict boar’s fertility. The expressions of PSP-I and PSP-II in spermatozoa from 21 individual boars with different fertility and litter size (litter size ranges from 10.3 – 14.2) were examined using qRT-PCR. Litter size was determined in 530 saws after artificial insemination (AI). In addition, sperm motility, motion kinematics, and capacitation status were measured using computer-assisted sperm analysis and Hoechst 33258/chlortetracycline fluorescence staining, respectively. PSP-I and PSP-II showed significantly negative correlation with litter size (r=0.578; P=0.006 and r=0.456; P=0.038, respectively). Furthermore, receiver-operating curves (ROC) was used to determine the accuracy for the prediction of boar fertility. Therefore we divided into 2 groups based on the median value of litter size. When selecting higher litter size group, PSP-I can predict litter size with overall accuracy 90.48% (sensitivity 88.89, specificity 91.67, negative predictive value 91.67, and positive predictive value 88.89) and PSP-II can predict with overall accuracy 81.82% (sensitivity 55.56, specificity 100.00, negative predictive value 76.47, and positive predictive value 100.00). Interestingly, PSP-I and PSP-II were found to increase 0.76 pups than average litter size (average 12.48) in tested boars. To best of our knowledge, this study is the first trial to investigate the correlation between PSP-I, PSP-II, and litter size. Therefore, we suggest that PSP-I and PSP-II could be considered as promising biomarkers for predicting male fertility and litter size outcome in field condition.

Mitochondrial and mitochondrial DNA (mtDNA) is maternally inherited in humans and most animals. The degradation of sperm-borne mitochondria after fertilization assures normal preimplantation embryo development and may prevent mitochondrial diseases derived from heteroplasmy. Although it has been known that ubiquitin-proteasome system (UPS) is the major degradation pathway of post-fertilization sperm mitochondria in mammals, it is unclear how the UPS, which is able to get rid of single protein molecule at a time, can eliminate whole sperm mitochondrial organelle. We considered that the autophagy receptors [sequestosome 1(SQSTM1), microtubule-associated protein 1 light chain 3 (LC3), and gamma-aminobutyric acid receptor-associated protein (GABARAP)] and the non-traditional mitophagy pathways involving UPS and the ubiquitin-binding protein dislocase, valosin-containing protein (VCP) may act independently or in concert during post-fertilization sperm mitophagy. We found that the association of SQSTM1 with sperm mitochondria was displayed in both pig and rhesus monkey zygotes after fertilization. Sperm mitochondrial proteins [mitochondrial trifunctional enzyme subunit alpha (HADHA), mitochondrial aconitase 2 (ACO2), and mitochondrial ATP synthase H+ transporting F1 complex β-subunit (ATP5B)] co-purified with the synthetic, SQSTM1-derived, ubiquitin-binding UBA domain were identified. Also, the accumulation of GABARAP-positive protein aggregates was observed around sperm mitochondrial sheaths in fertilized oocytes, which reflects autophagosome formation. Furthermore, the inhibition of VCP delayed the process of sperm mitophagy and completely blocked it when embryos were co-injected with autophagy-targeting antibodies, such as anti-SQSTM1 and/or anti-GABARAP. Thus, both SQSTM1-dependent autophagy pathway and VCP-mediated proteasomal proteolysis facilitate post-fertilization sperm mitophagy in mammals. This explains how the proteolytic pathway can coordinate autophagy pathway to degrade the sperm mitochondrial sheath inside the fertilized oocyte.

Endocrine disruptors bind to hormone receptors on sperm membrane, therefore spermatozoa are potentially a useful model for examining estrogenic activities of endocrine disruptors. The objective of this study was to compare the effects of two xenoestrogenic compounds [genistein (Gen) and 4-tert-octylphenol (OP)] to those of two steroids [estrogen (E2) and progesterone (P4)] on boar sperm % motility and motion kinematics of in vitro. Porcine spermatozoa were incubated with various concentrations (0.001～100 μM) of each chemical for 15 or 30 min, and then assessed % motility and sperm motion kinematics using computer assisted sperm analyzer (CASA). Each chemical decreased sperm % motility, and OP decreased VSL and VAP compared with untreated control(p<0.05). E2 stimulated the motion kinematic changes except VCL. Moreover, Gen had effects on VCL and VAP alterations after 30 min incubation. In summary, since all chemicals studied effectively altered sperm % motility and motion kinematics, it was concluded that porcine spermatozoa could be a useful model for in vitro screening of potential endocrine disruptors.

본 연구는 정액의 보존 기간 동안 정액의 질적 변화를 알아보고자 시행하였다. 돼지 정액을 Beltsville Thawing Solution (BTS)에 희석한 후 17'C 에서 5일 동안 보존하였다. 보존 기간 동안 정자의 운동성(%)과 linearity는 3일째부터 유의하게 감소하였으나, 다른 운동 역학 변수에서는 유의적 변화를 나타내지 않았다. 또한, 5일 동안 정액을 보존할 경우 첨체의 온전성에도 변화가 없었다. 그러나 제 4일째부터 첨체 변화가 야기된 정자는 유의적으로 증가하였으나, 수정능 획득이 일어난 정자는 유의적으로 감소하였다. 정액의 보존 기간 동안 첨체의 온전성의 유의적 변화가 없었다. 즉, 보존 기간 3일동안 정자의 질적 운동성 및 첨체 온전성에는 유의적인 변화가 없었으므로 상업용 돼지 액상정액은 17'C 에서 적어도 3일간 수정능력을 만족스럽게 유지함을 보여준다.