Establishment, Culture, and Characterization of Guinea Pig Fetal Fibroblast Cell

Establishment of Guinea pig fetal fibroblast cells and their biological evaluation before and after cryopreservation were the main purposes of this study. After determination of the proper age of pregnancy by ultrasonography, 30 days old fetuses of Guinea pigs were recovered. Their skins were cut into small pieces (1 mm2) and were cultured. When reaching 80–90% confluence, the cells were passaged. Cells of the second and eighth passages were cultured in 24-well plates (4×104cells/well) for 6 days and three wells per day were counted. The average cell counts at each time point were then plotted against time and the population doubling time (PDT) was determined. Then, vials of cells (2×106cells/mL) were cryopreserved for 1 month and after thawing, the cell viability was evaluated. The PDT of the second passage was about 23 h and for the eighth passage was about 30 h. The viability of the cultures was 95% in the second passage and 74.5% in the eighth passage. It was shown that the Guinea pig fetal fibroblast cell culture can be established using the adherent culture method while, after freezing, the viability indices of these cells were favorable.

49 EFFECTS OF CULTURE CONDITIONS AND GENE TRANSFECTION ON THE DEVELOPMENT OF BOVINE SOMATIC CELL NUCLEAR TRANSFER EMBRYOS

Somatic cell nucleus transfer (SCNT) and in vitro culture of reconstructed embryos are the pivotal steps for successful cloning and generation of transgenic cattle. The aim of the study was to determine the influence of different cell fusion parameters, maturation, and culture conditions and the type of a cell line (bovine fetal fibroblast cell lines with or without gene transfection) on SCNT blastocyst development. Slaughterhouse-derived oocytes were matured for 17 h in TCM-199 (Sigma, St. Louis, MO, USA) supplemented with 0.05 µg mL–1 of epidermal growth factor (EGF) and 15 IU mL–1 of hCG/eCG (Intervet, PG600) or 10 µg mL–1 of FSH and 12.5 mU mL–1 of LH (Sioux Biochemical Inc., Sioux Center, IA, USA). Four fetal fibroblast cell lines (4 to 5 passages) and identical cell lines transfected with plasmid containing either human erythropoietin, FSH, growth hormone, or insulin-coding cDNA under β-casein promoter (7 to 9 passages) were used for SCNT. Cell fusion was induced by 2 direct-current pulses in 0.5 or 0.2 micro fusion chambers (Eppendorf Multiporator) using one of the following treatments: 100V for 15 µs (F1), 65V for 25 µs (F2), 65V for 20 µs (F3; all in a 0.5-mm chamber), or 36V for 25 µs (F4; 0.2-mm chamber). Fused complexes were activated with 4 µg mL–1 of Ca-ionophore for 4 min and then incubated for 5 h in 2 mM DMAP. The embryos were cultured in SOFaaci medium (Holm et al. 1999) or in commercial SOF medium (Minitüb GmbH, Tiefenbach, Germany) for 7 days. Data were analysed by ANOVA and the chi-square test. The results of the study showed that the cleavage rate of the reconstructed embryos was influenced by the fusion regimen (P < 0.05) but not by the donor cell type (P < 0.05). Treatments F2 and F3 resulted in cleavage rates higher (P < 0.05) than F1 and F4 (77.2, 82.0, 62.8, and 63.1%, respectively). Blastocyst yield was not significantly influenced by the different in vitro maturation (IVM) media – altogether, addition of FSH/LH resulted in 14.6% (158/1079) and EGF + hCG/eCG in 13.2% (73/554) of blastocysts (P < 0.05). The combination of TCM-199 + FSH/LH and SOFaaci resulted in 19.6% (79/403) blastocysts compared with 12.4% (74/596) when the same IVM medium and commercial SOF were used (P < 0.05). The use of transgenic cell lines for cloning led to a lower overall blastocyst rate (10.9%, 38/348) than use of non-transfected cell lines (17.7%, 115/651; P < 0.05), whereas the differences were 5.6 and 4.1 percentage points for SOF and SOFaaci, respectively. There were no significant differences between the individual cell lines within a cell line type. In conclusion, the optimization of the fusion parameters and in vitro culture (IVC) conditions led to improved blastocyst yields. In vivo development potential of the generated embryos still has to be evaluated in further studies. This study was supported by Project EU29023 of Enterprise Estonia, CCRMB, targeted grant SF1080045s07, and grant P8001 from the Estonian University of Life Sciences.