• Journal of Veterinary Clinics
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• v.37 no.2
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• pp.61-66
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• 2020

Nickel is a nutritionally essential trace element that plays an important role in the immune system of several animal species. The aim of this study was to examine the effect of nickel chloride on chemotactic activity of peripheral blood polymorphonuclear cells (PMNs) and whether this effect is associated with interleukin (IL)-8 and a nuclear factor-kappa B (NF-κB)-dependent pathway. Peripheral blood mononuclear cells (PBMCs) and PMNs were isolated by Percoll solution (Specific gravity; 1.080) and 1.5% dextran treatment, respectively. A modified Boyden chamber assay was used to measure the chemotactic activity of PMNs. The level of IL-8 in culture supernatant from PBMCs was measured by enzyme-linked immunosorbent assay (ELISA). Both of PBMCs and PMNs exhibited a low viability when cultured with concentration of greater than 1,000 μM of nickel chloride for 24 h. Thus, nickel chloride was used at concentration of 500 μM, which preserved cell viability. Treatment with nickel did not directly affect the chemotactic activity of PMNs. However, the chemotactic activity of PMNs was remarkably increased by culture supernatant from PBMCs treated with nickel chloride (500 μM) for 24 h. Recombinant porcine IL-8 polyclonal antibody (pAb) neutralized the enhancing effect on the chemotactic activity of PMNs by culture supernatant from PBMCs treated with nickel and this culture supernatant had higher IL-8 levels than the culture supernatant from untreated PBMCs. In addition, n-tosyll-phenylalanine chloromethyl ketone (TPCK), a NF-κB inhibitor, antagonized the enhancing effect on the chemotactic activity of PMNs by the culture supernatant from PBMCs treated with nickel. These results suggested that nickel stimulates porcine PBMCs to produce IL-8, which increases the chemotaxis of PMNs via NF-κB-dependent pathway.

• Korean Journal of Animal Reproduction
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• v.14 no.4
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• pp.253-261
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• 1990

This study was carried out to investigate the factors affecting development in vitro of follicular oocytes fertilized in vitro in Korean Native Cattle. The bovine ovaries were obtained at a slaughter house and the follicular oocytes were recovered by aspirating the follicular fluid from the visible follciles of 3~6mm. The bovine oocytes were matured in vitro for 20~24 hours in TCM0-199 containing 10% FCS and hormones (0.02AU/ml FSH, 10$\mu\textrm{g}$/ml LH, 1$\mu\textrm{g}$/ml estradiol-17$\beta$). The matured oocytes were fertilized in vitro using Percoll-separated frozen-thawed spermatozoa in BO solution containing caffeine(5mM) and heparin(10$\mu\textrm{g}$/ml). Twenty-four hours after insemination, the oocytes were cultured in vitro and then the effects of cumulus cell layer, co-culture with cumulus cells, bovine oviduct epithelial cells from ampulla or isthmus on development of ova, were studied. The results obtained are summarized as follows : 1. The in vitro development degree of oocytes attached with compact and dense layered cumulus cells was higher than that with 3~4 layered cumulus cells to be 9~16cells(P<0.01). 2. When the in vitro fertilized oocytes were co-cultured with bovine oviduct epithelial cells or cumulus cells, the development rate to be morula was 20.2% and 12.7%, respectively and the rates were higher than that of control, 2.1%(P<0.05). 3. The development rate to be morula was 15.8% and 23.8%, respectively when the in vitro fertilized oocytes were co-cultured with bovine oviduct epithelial cells from ampulla or isthmus, and the rates were higher than that of control, 0%(P<0.05%).

• Journal of Animal Reproduction and Biotechnology
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• v.37 no.2
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• pp.130-135
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• 2022

Epididymal sperm cryopreservation provides a potential method for preserving genetic material from males of endangered species. This pilot study was conducted to develop a freezing method for tiger epididymal sperm. We evaluated post-thaw sperm condition using testes with intact epididymides obtained from a Siberian tiger (Panthera tigris altaica) after castration. The epididymis was chopped in Tyrode's albumin-lactate-pyruvate 1x and incubated at 5% CO₂, 95% air for 10 min. The Percoll separation density gradient method was used for selective recovery of motile spermatozoa after sperm collection using a cell strainer. The spermatozoa were diluted with modified Norwegian extender supplemented with 20 mM trehalose (extender 1) and subsequent extender 2 (extender 1 with 10% glycerol) and frozen using LN₂ vapor. After thawing at 37℃ for 25 s, Isolate^® solution was used for more effective recovery of live sperm. Sperm motility (computerized assisted sperm analysis, CASA), viability (SYBR-14 and Propidium Iodide) and acrosome integrity (Pisum sativum agglutinin with FITC) were evaluated. The motility of tiger epididymal spermatozoa was 40.1 ± 2.0%, and progressively motile sperm comprised 32.7 ± 2.3%. Viability was 56.3 ± 1.6% and acrosome integrity was 62.3 ± 4.4%. Cryopreservation of tiger epididymal sperm using a modified Norwegian extender and density gradient method could be effective to obtain functional spermatozoa for future assisted reproductive practices in endangered species.

• Reproductive and Developmental Biology
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• v.29 no.2
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• pp.127-131
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• 2005

The objective of this study was to examine the effect of EGF on meiotic maturation and pronuclear (PN) formation of porcine oocytes. Prepubertal gilt cumulus-oocyte-complexes (COCs) aspirated from $2\~6mm$ follicles of abbatoir ovaries were matured in TCM199 containing 0.1mg/ml cysteine, $0.5{\mu}/ml$ FSH and LH, and EGF (0, 5, 10, 20, 40 ng/ml) for 22 hr at $39^{\circ}C$ in a humidified atmosphere of $5\%$ $CO_2$ in air. They were then cultured for an additional 22hr without hormones. In Experiment 1, to examine the nuclear maturation at 44hr of culture, the expanded cumulus cells were removed by vortexing for 1 min in 3 mg/ml hyaluronidase. The oocytes were fixed in acetic acid: methanol (1:3, v/v) at least for 48 hr and stained with $1\%$ orcein solution for 5 min. Nuclear status was classified as germinal vesicle (GV), germinal vesicle breakdown (GVBD), prophase-metaphase I (PI-MI), and PII-MII under microscope. In Experiment 2, to investigate PN formation, oocytes were fertilized with Percoll-treated freshly ejaculated sperm $(1\times10^5\; cells/ml)$ in mTBM with $0.3\%$ BSA and 2mM caffeine for 5hr, and cultured in NCSU-23 medium with $0.4\%$ BSA. At 6hr of culture, the embryos were fixed in $3.7\%$ formaldehyde for 48hr and stained with 10ug/ml propidium iodide for 30 min. PN status was classified as no or one PN (unfertilized), 2 PN (normal fertilized) and $\geq3$ PN (polyspermy). Differences between groups were analyzed using one-way ANOVA after arc-sine transformation of the proportional data. The rate of oocytes that had reached to PII-MII were significantly (P<0.05) higher in all groups added EGF than that of non-treated group $(67\%)$, but it did not differ among the all added groups $(86\%,\;85\%,\;79\%\;and\;81\%$, in 5, 10, 20 and 40 ng/ml EGF, respectively). No differences on the incidence of 2PN were observed in all treated groups $(25\%,\;30\%,\;33\%,\;29\%\;and\;29\%$, in 0, 5, 10, 20 and 40 ng/ml EGF, respectively), however, in non-treated group, polyspermy tended to be increased ($66\%\;vs\;. 58\%,\;54\%,\;52\%\;and\;55\%$, 0 vs. 5, 10, 20, 40 ng/ml EGF, respectively). These results suggest that EGF can be effectively used as an additive for enhancing oocyte maturation and reducing the incidence of polyspermy in pig.