Cryopreservation of porcine ovarian tissue by vitrification method is a promising approach to preserve genetic materials for future use. However, information is not enough and technology still remains in a challenge stage in pig. Therefore, the objective of present study was to determine possibility of vitrification method to cryopreserve porcine ovarian tissue and to confirm an occurrence of cryoinjuries. Briefly, cryoinjuries and apoptosis patterns in vitrified-warmed ovarian tissue were examined by histological evaluation and TUNEL assay respectively. In results, a damaged morphology of oocytes was detected among groups and the rate was significantly (p < 0.05) lower in vitrification group (25.8%) than freezing control group (67.7%), while fresh control group (6.6%) showed significantly (p < 0.05) lower than both groups. In addition, cryoinjury that form a wave pattern of tissues around follicles was found in the frozen control group, but not in the fresh control group as well as in the vitrification group. Apoptotic cells in follicle was observed only in freezing control group while no apoptotic cell was found in both fresh control and vitrification. Similarly, apoptotic patterns of tissues not in follicle were comparable between fresh control and vitrification groups while freezing control group showed increased tendency. Conclusively, it was confirmed that vitrification method has a prevention effect against cryoinjury and this method could be an alternative approach for cryopreservation of genetic material in pigs. Further study is needed to examine the viability of oocytes derived from vitrified-warmed ovarian tissue.

In our previous studies, the cardiac xenotransplantation from an alpha-1,3-galactosyltransferase knockout pig (GT-MCP-MCP) to cynomolgus monkeys showed a mean survival of 38 days. The objective of this study is to genetically upgrade the GT-MCP-MCP pig, to further enhance membrane cofactor protein (MCP) expression and to express an endothelial specific thrombomodulin (TBM). MCP is a complement regulatory protein and TBM is a coagulation inhibitor. As the dicistronic cassette for wild-type-based MCP and TBM concurrent expressions does not show any increase of MCP, we optimized the MCP codon usage (mMCP) and substituted mMCP for MCP. When the mMCP-TBM cassette was transfected to HeLa cells, we were able to find an increased expression of MCP and endothelial cell-specific TBM expression. The cassette was then transfected into ear-skin fibroblasts isolated from one-month-old #23-4 of a GT-MCP-MCP pig, and the cell populations expressing MCP were obtained by MACS cell sorting. We performed a single cell culture of the selected cells, and obtained clones over expressing 90% MCP. The cells of a clone were used as a donor for nuclear transfer and generated GT-MCP/-MCP/mMCP/TBM pig. The transgenic pig was confirmed to be carrying the cells expressing MCP and functioning as an inhibitor against the cytotoxic effect of normal monkey serum, comparable with donor cells. Thus, we believe that the GT-MCP/-MCP/mMCP/TBM transgenic pig would be potential for the prolongation of xenograft survival in the recipients.

Acute vascular rejection has been known as a main barrier occurring in a xenograted tissue of alpha 1,3-galactosyltransferase knock-out (GalT KO) pig into a non-human primate (NHP). Adenosine which is a final metabolite following sequential hydrolysis of nucleotide by ecto-nucleotidases such as CD39 and CD73, act as a regulator of coagulation, and inflammation. Thus xenotransplantation of CD39 and CD73 expressing pig under the GalT KO background could lead to enhanced survival of recipient NHP. We constructed a human CD39 and CD73 expression cassette designed for endothelial cell-specific expression using porcine Icam2 promoter (pIcam2-hCD39/hCD73). We performed isolation of endothelial cells (pAEC) from aorta of 4 week-old GalT KO and membrane cofactor protein expressing pig (GalT-MCP/-MCP). We were able to verify that isolated cells were endothelial-like cells using immunofluorescence staining analysis with von Willebrand factor antibody, which is well known as an endothelial maker, and tubal formation assay. To find optimal condition for efficient transfection into pAEC, we performed transfection with GFP expression vector using four programs of nucleofection, M-003, U-023, W-023 and Y-022. We were able find that the program W-023 was optimal for pAEC with regard to viability and transfection efficiency by flow cytometry and fluorescent microscopy analyses. Finally, we were able to obtain GalT-MCP/-MCP/CD39/CD73 pAEC expressing CD39 and CD73 at levels of 33.3% and 26.8%, respectively. We suggested that pACE isolated from GalT-MCP/-MCP pig might be provided as a basic resource to understand biochemical and molecular mechanisms of the rejections and as an alternative donor cells to generate GalT-MCP/-MCP/CD39/CD73 pig expressing CD39 and CD73 at endothelial cells.

It is very difficult to get the information about semen quality analysis in transgenic pigs because of limited numbers and research facilities. Therefore, in the present study, we analyzed the semen quality of transgenic boars generated for xenotransplantation research. Briefly, the semen samples were collected from 5 homozygous α1,3-Galactosyltransferase knock-out (GalT-/-) transgenic boars and immediately transported to the laboratory. These semen samples were decupled with DPBS and conducted to analyze semen parameters by a computer-assisted semen analysis (CASA) system. The boar semen were examined all 12 parameters such as total motility (TM), curvilinear velocity (VCL), straight line velocity (VSL), average path velocity (VAP), and hyperactivated (HYP), etc. In results, among the 5 GalT-/- boars, three boars (#134, 144, and 170) showed normal range of semen parameters, but #199 and 171 boars showed abnormal ranges of semen parameters according to standard ranges of semen parameters. Unfortunately, #171 boar showed azoospermia symptom with rare sperm counts in the original semen. Conclusively, assessment of semen parameters by CASA system is useful to pre-screening of reproductively healthy boar prior to natural mating and artificial insemination for multiplication and breeding.

The present study was conducted to investigate the effect of caffeine and theophilline on sperm motility during in vitro fertilization (IVF). Briefly, commercial boar semen was centrifuged and resuspended (5x107 sperms/ml) with fertilization medium (mTBM) supplemented with 2 mM caffeine (Caf), 5 mM theophylline (The), 2 mM caffeine + 5mM theophylline (Caf + The), and not supplemented control. The semen parameters of the four groups were analyzed by computer-assisted semen analysis (CASA, Medical Supply Co. Ltd) system at 6 h as time for IVF at 38.5 C under 5 % CO2 in air. The groups were examined 11 semen parameters such as total motility (TM), curvilinier velocity (VCL), straight-line velocity (VSL), average-path velocity (VAP), and hyperactivated (HYP), etc. A total motility of control group (41.3 %) at 6 h showed significantly (P<0.05) higher than those of other groups (Caf, 37.2; The, 35.2; Caf + The, 30.1 %). Results from many other sperm parameters indicated that the theophylline and caffeine negatively affected on sperm motility during IVF. These results suggested that the supplementation of caffeine and/or theophylline was not essential for IVF in pigs. To prove this suggestion, further studies are needed to analyze fertility and embryonic development after IVF with or without the supplementation of caffeine and/or theophylline.

Although piglets have been delivered by embryo transfer (ET) with in vitro produced (IVP) embryos and blastocysts, a success rate has still remained lower level. Unlike mouse, human, and bovine, it is difficult to a production of piglets by in vitro fertilization (IVF) because of an inappropriate in vitro culture (IVC) system in pig. Therefore, the present study was conducted to investigate whether minimized exposure time in IVC can improve the pregnancy and delivery rates of piglets. Immediately after IVM, the oocytes were denuded and co-incubated with freshly ejaculated boar semen for 3.5 to 4 hours at 38.5 ˚C under 5% CO2 in air. To avoid long-term exposure to in vitro state, we emitted IVC step after IVF. After that the presumptive zygotes were transferred into both oviducts of the surrogate on the same day or 1 day after the onset of estrus. Pregnancy was diagnosed on day 28 after ET and then was checked regularly every month by ultrasound examination. The 3 out of 4 surrogates were determined as pregnant (75%) and a total of 5 piglets (2 females and 3 males) were delivered at 118.3 ± 2.5 days of pregnancy period. In conclusion, a short-term exposure time may be an important factor in the production of IVP-derived piglets. It can be apply to the in vitro production system of transgenic pig by IVF, cloning, and pronuclear microinjection methods.

To overcome the hyperacute immune rejection during pig-to-non-human primates xenotranasplantation, we have produced and bred α-1,3-galactosyltransferase knock-out (GalT —/—) pigs. In this study, the somatic cells and tissues from the GalT —/— pigs were characterized by an analysis of the expression of Galα-1,3-Gal (α-Gal) epitope. Briefly, ear fibroblast cell lines of 19 homozygous GalT —/— pigs were established and cryopreserved. The expression of α-Gal epitope in the cells was measured by fluorescence activated cell sorter (FACS) analysis using BS-I-B4 lectin. Also, the homozygous (GalT —/—) cells and tissues samples were immunostained with BS-I-B4 lectin for analysis of α-Gal epitope expression. The results showed that the expression of α-Gal epitope in GalT —/— cells (0.2 %) were significantly (p< 0.05) down-regulated to the range of cynomolgus monkey fibroblast (0.2 %) cells compared to heterozygous (GalT —/+) (9.3 %) and wild type (GalT +/+) (93.7 %) fibroblast cells. In the immunostaining results, while the expression of α-Gal epitope was detected a partly in GalT —/+ cells and mostly in GalT +/+ cells, it was almost not detected in the GalT —/— cells. Also, immunostaining results from various tissues of the GalT —/— pig showed that the expression of α-Gal epitope was not detectable, whereas various tissues from GalT +/+ pig showed a strong expression of α-Gal epitope. Our results demonstrated that α-Gal epitope expressions from GalT —/— pigs were successfully knocked out to prevent hyperacute immune rejection for further study of xenotransplantation.

To improve survival rates of vitrified pig oocytes, the treatment of cytoskeletal stabilizer on an appropriate time is one of the possible approaches. However, the exact treatment timing and effect of cytoskeletal stabilizer such as cytochalasin B (CB) is not well known during oocyte vitrification procedures. Thus, the present study was conducted to determine optimal treatment timing of CB during vitrification and warming procedures. In experiment 1, the survival rates of the post-warming pig oocytes were analyzed by fluorescein diacetate (FDA) assays with 4 classifications. In results, post-warming oocytes showed significantly (p<0.05) decreased number of alive oocytes (31.8% vs. 86.4%) compared to fresh control. In detail, the significant difference (p<0.05) was found only in strong fluorescence (18.2% vs. 70.5%) not in intermediate fluorescence groups (13.6% vs. 15.9%). In experiment 2, CB was treated before (CB-Vitri) and after (Vitri-CB) vitrification. In results, group of Vitri-CB showed significantly (p<0.05) higher (91.6%) survival rates compared to group of CB-Vitri (83.7%), significantly (p<0.05) and comparable with group of Vitri Control (88.7%) by morphological inspection. In FDA assay results, group of Vitri-CB showed significantly (p<0.05) higher (44.2%) survival rates compared to groups of CB-Vitri (36.7%) and Vitri Control (35.1%). In conclusion, the increased survival rates of post-warming pig oocyte treated with Vitri-CB method are firstly described here. The main finding of present study is that the CB treatment during recovery could be helpful to refresh the post-warming pig oocyte resulting its improved survival rates.

The Korean native pig (KNP) have been considered as animal models for animal biotechnology research because of their relatively small body size and their presumably highly inbred status due to the closed breeding program. However, little is reported about the use of KNP for animal biotechnology researches. This study was performed to establish the somatic cell nuclear transfer (SCNT) protocol for the production of swine leukocyte antigens (SLA) homotype-defined SCNT KNP. The ear fibroblast cells originated from KNP were cultured and used as donor cell. After thawing, the donor cells were cultured for 1 hour with 15 μM roscovitine prior to the nuclear transfer. The numbers of reconstructed and parthenogenetic embryos transferred were 98 ± 35.2 and 145 ± 11.2, respectively. The pregnancy and delivery rate were 3/5 (60%) and 2/5 (40%). One healthy SLA homotype-defined SCNT KNP was successfully generated. The recipient-based individual cloning efficiency ranged from 0.65 to 1.08%. Taken together, it can be postulated that the methodological establishment of the production of SLA homotype-defined cloned KNP can be applied to the generation of transgenic cloned KNP as model animals for human disease and xenotransplantation researches.