Synthesis of functional enzymes involved in glutathione production during linear motility in boar sperm.

Sperm cells are highly susceptible to oxidative stress, which decreases their motility and fertility. However, glutathione (GSH) plays a critical role in protecting sperm cells from oxidative damage, a common byproduct of mitochondrial oxidative phosphorylation. On the other hand, GSH biosynthesis in sperm is limited by the availability of cysteine (Cys), which is inherently unstable and found at low concentrations in boar seminal plasma.

Elite mobility and continuity during a regime change.

How does a regime change influence elite mobility? By collecting data on elites after the Meiji Restoration in Japan in 1868, through which Japan transitioned from a feudal regime to a modern regime, we provide new evidence that the impact of the regime change on elite mobility varies across the stages of the regime change. We analyze the impact of the regime change from two aspects: (1) the composition of elites or elite membership and (2) the internal hierarchy within them. The regime change opened an opportunity for commoners to join the elite group.

Gene Expression and Protein Synthesis in Mitochondria Enhance the Duration of High-Speed Linear Motility in Boar Sperm.

Sperm motility patterns are continuously changed after ejaculation to fertilization in the female tract. Hyperactivated motility is induced with high glucose medium or the oviduct fluids , whereas sperm maintain linear motility in the seminal plasma or the uterine fluids containing low glucose. Therefore, it is estimated that sperm motility patterns are dependent on the energy sources, and the mitochondrial oxidative phosphorylation is activated to produce ATP in low glucose condition.

Addition of oxytocin to semen extender improves both sperm transport to the oviduct and conception rates in pigs following AI.

Oxytocin (OXT) contained in boar semen is known to produce uterine contraction; therefore, we hypothesized that the co-injection of OXT with sperm would improve artificial insemination (AI) using liquid or frozen-thawed boar sperm. We initially examined whether OXT added to semen extender improved sperm transport to the oviduct. Although the addition of OXT did not affect the fresh or frozen-thawed sperm motility or acrosomal integrity, it significantly increased the number of sperm in the oviduct at 6 h after AI injection with OXT, as compared with the control (P < 0.

Anti-bacterial factors secreted from cumulus cells of ovulated COCs enhance sperm capacitation during in vitro fertilization.

Problem: The aim of this study was to find immune-related genes expressed in cumulus cells of ovulated cumulus oocyte complexes (COCs) and to clear the functional roles during fertilization process.

Method Of Study: Ovulated COCs were collected from oviduct 16 hr after the hCG injections followed by eCG priming. The cumulus cells were used for RT-PCR or western blotting study.

New strategies of boar sperm cryopreservation: development of novel freezing and thawing methods with a focus on the roles of seminal plasma.

Cryopreservation of boar spermatozoa offers an effective means of long-term storage of important genetic material. Many researchers have investigated how to improve reproductive performance by artificial insemination (AI) using cryopreserved boar spermatozoa. Recently, we and other groups reported that high conception rates (70-80%) can be achieved by AI with frozen-thawed boar spermatozoa using a modified temperature program during freezing, or a novel cryopreservation extender to improve sperm quality (including sperm survivability, motility, membrane status and fertilization ability) after thawing, or a novel sperm infusion method, deep intra uterine insemination.

Artificial insemination with seminal plasma improves the reproductive performance of frozen-thawed boar epididymal spermatozoa.

Frozen-thawed epididymal spermatozoa have good fertilization capability in vitro; however, their artificial insemination conception rate is less than half of that of frozen-thawed ejaculated spermatozoa. Because the addition of seminal plasma to the thawing solution enhances the in vivo fertilizing ability of frozen-thawed ejaculated spermatozoa, we hypothesized that the reproductive performance of frozen-thawed epididymal spermatozoa could also be improved by the inclusion of seminal plasma. When frozenthawed epididymal spermatozoa were incubated for up to 6 hours, the motility of the sperm significantly decreased in a time-dependent manner.

Positive feedback loop between prostaglandin E2 and EGF-like factors is essential for sustainable activation of MAPK3/1 in cumulus cells during in vitro maturation of porcine cumulus oocyte complexes.

During in vitro maturation of porcine cumulus-oocyte complexes (COCs), follicle-stimulating hormone (FSH) increases both prostaglandin E2 (PGE2) production and the expression levels of EGF-like factors. The ligands act on cumulus cells by the autocrine system due to their specific receptors, EP2, EP4, or EGF receptor. When each pathway is suppressed by inhibitors, complete cumulus expansion and oocyte maturation do not occur.

Toll-like receptors (TLR) 2 and 4 on human sperm recognize bacterial endotoxins and mediate apoptosis.

Background: Bacterial infections of the genital tract are one of the most serious causes of infertility in males. In some human patients with poor semen quality, leukocytospermia has been observed. Because leukocytes express the bacterial-lipopolysaccharide (LPS) responsive Toll-like receptor (TLR) signaling cascade and secrete tumor necrosis factor-α, secreted cytokines comprise one, but probably not the only, class of factors that can impact sperm motility.

The addition of calcium ion chelator, EGTA to thawing solution improves fertilizing ability in frozen-thawed boar sperm.

In our previous study, seminal plasma effectively suppressed the induction of sperm to capacitation-like status and acrosome loss during the thawing process. However, because boar seminal plasma is contaminated with various kinds of bacteria and/or viruses, it is necessary to develop a thawing solution without animal-derived materials. In this study, we focused on the increase of intracellular Ca(2+) ([Ca(2+)](i)) in sperm after thawing and the negative effects of sperm qualities.

Polymyxin B neutralizes bacteria-released endotoxin and improves the quality of boar sperm during liquid storage and cryopreservation.

Gram negative bacteria are the predominant type detected in boar semen. Since these bacteria release lipopolysaccharide (LPS), and because polymyxin B (PMB) neutralizes LPS activity, the objective was to improve techniques for long-term storage of boar sperm by testing the beneficial effects of PMB. In the present study, LPS bound directly to the head region of sperm, decreased sperm motility, and induced sperm apoptosis.

Improved conception rates in sows inseminated with cryopreserved boar spermatozoa prepared with a more optimal combination of osmolality and glycerol in the freezing extender.

Cryoprotectant agents (CPAs) are added in freezing extenders to prevent intracellular ice crystal formation. However, it has been reported that high dose of CPAs confer toxicity on spermatozoa. Recently, the reduction of intracellular water by a high osmolality solution has also resulted in the suppression of ice crystal formation in spermatozoa, suggesting that the optimal combination of glycerol concentration and freezing extender osmolality could contribute to the development of effective sperm cryopreservation techniques.

Sequential exposure of porcine cumulus cells to FSH and/or LH is critical for appropriate expression of steroidogenic and ovulation-related genes that impact oocyte maturation in vivo and in vitro.

In this study, we collected follicular fluid, granulosa cells, and cumulus cells from antral follicles at specific time intervals following equine chorionic gonadotropin (eCG) and human chorionic gonadotropin (hCG) treatment of gilts. The treatment with eCG increased the production of estrogen coordinately with up-regulated proliferation of granulosa and cumulus cells. eCG also induced the expression of LHCGR and PGR in cumulus cells and progesterone accumulation was detected in follicular fluid prior to the LH/hCG surge.

Hyaluronan fragments generated by sperm-secreted hyaluronidase stimulate cytokine/chemokine production via the TLR2 and TLR4 pathway in cumulus cells of ovulated COCs, which may enhance fertilization.

The toll-like receptor (TLR) system is expressed in cumulus cells of ovulated cumulus-oocyte complexes (COCs) and is activated by bacterial lipopolysaccharides (LPS). However, the endogenous ligand(s) for the TLRs and the physiological role(s) in ovulated COCs remain to be defined. Based on reports that hyaluronan fragments can activate TLR2 and TLR4 in macrophages, and that ovulated COCs are characterized by a hyaluronan-rich matrix, we cultured ovulated mouse COCs with purified hyaluronan fragments, treated them with purified hyaluronidase or exposed them to sperm as a physiologically relevant source of hyaluronidase.

Synaptosomal-associated protein 25 gene expression is hormonally regulated during ovulation and is involved in cytokine/chemokine exocytosis from granulosa cells.

During ovulation, granulosa cells and cumulus cells synthesize and secrete a wide variety of factors including members of the IL cytokine family via the process of exocytosis. Exocytosis is controlled by the soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor complex consisting of proteins residing in the vesicle membrane and the plasma membrane. One of the soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor proteins, synaptosomal-associated protein (SNAP)25, is expressed abundantly in neuronal cells and is also induced transiently in the rat ovary in response to LH.

Expression of two progesterone receptor isoforms in cumulus cells and their roles during meiotic resumption of porcine oocytes.

The present study aimed to investigate progesterone receptor (PR) gene expression in cumulus cells and their roles during meiotic resumption of porcine oocytes. The amount of PR-A or PR-B mRNA was analyzed by RT-PCR using primer sets for the PR-B region or the PR-A/B common region. The level of PR-B mRNA in cumulus cells was up-regulated by FSH and LH during the first 8 h of cultivation but the level significantly decreased at 12 h.

LH reduces proliferative activity of cumulus cells and accelerates GVBD of porcine oocytes.

It has been reported that LH receptor (LHR) mRNA is not detected in cumulus cells of porcine cumulus-oocyte complexes (COCs) just after collection from small antral follicles. The present study showed that the formation of LHR in cumulus cells was up-regulated by the cultivation with 20 ng/ml FSH. When the newly synthesized receptors were stimulated by 1.

Production of progesterone from de novo-synthesized cholesterol in cumulus cells and its physiological role during meiotic resumption of porcine oocytes.

To investigate the role of factors secreted by cumulus cells during meiotic resumption of porcine oocytes, 1, 5, 10, or 20 cumulus-oocyte complexes (COCs) were cultured in each well of a culture dish containing 300 microl of maturation medium for 20 h. There was a significant positive correlation between the rate of germinal vesicle breakdown (GVBD) and the number of COCs cultured in each well for 20 h. The level of progesterone in the medium in which COCs had been cultured for 20 h also rose significantly with an increase in the number of COCs cultured in each well.