This experiment was to investigate whether the mitochondria function assessment can be used for the prediction of sperm fertility through examining the correlation between mitochondria fluoromicroscopic frequency of frozen-thawed eight Hanwoo bull semen using rhodamine123 (R123) and in vitro embryo development following fertilization. Individual sperm were stained in 5ug/mL R123-added calcium-free Sp-TALP for 30 min at 0 h, 6 h, 12 h and 24 h after thawing and examined their mid-piece under an epifluorescence microscope using 495 nm excitation filter (x1,000). Three replications were taken, and at least 300 sperm per individual were examined. When semen samples were separated into two groups (good and poor) by sperm motility and fluorescent frequencies at just after thawing, average fluorescent frequencies were remarkably reduced as time going (0 h; 53.29~72.94%, 6 h; 21.40~58.90%, 12 h; 8.26~25.93%, 24 h; 1.00~13.78%, irrespective of selected group, and there were no differences at 6 h or 12 h after thawing between selected groups but indicated significant difference at 24 h after thawing (p<0.05). In vitro fertilization rates in good and poor groups ranging 70.8~77.8% and 52.1~84.5%, respectively, were not significantly different. However, in vitro development rates of the same groups ranging 25.7~40.0% and 12.9~1.8%, respectively, were significant different (p<0.05). These results demonstrate that mitochondria fluoromicroscopic assessment of frozen-thawed bovine sperm may be used as a criterion to select more fertile sperm.

Epidermal growth factor (EGF) induces well-documented mitogenic and differentiating effects on murine and bovine preimplantation embryos. However, the effects of EGF on apoptosis and implantation-related gene expression in bovine embryos developing in vitro have not been evaluated. The objective of this study was to determine the effects of exogenous EGF in the presence and absence of BSA on the preimplantation development of bovine embryos. In addition, we measured cell number, apoptosis, and expression of apoptosis and implantation-related genes of the blastocysts that developed in these culture conditions. In vitro produced bovine embryos were randomly cultured in the same medium containing 0 or 10 ng/ml EGF in the presence and absence of 0.8% BSA. More 2-cell embryos developed into blastocysts at day 7 when BSA was present than when BSA was absent. The addition of 10 ng/ EGF into the medium did not significantly increase the developmental rate and the cell numbers per blastocyst. However, addition of EGF in the presence of 0.8% BSA significantly reduced the degree of apoptosis in the blastocysts (P<0.01). To investigate whether EGF modulates mRNA expression of apoptosis-related genes, mRNA was prepared from single blastocysts and each preparation was subjected to RT-PCR for Bcl-2 and Bax transcripts. EGF did not alter the relative abundance of Bax gene expression in the presence of BSA, but increase Bcl-2 (P<0.01) The relative abundance of Interferon tau expression was increased by EGF treatment in the presence of BSA. These results suggest that EGF and BSA synergistically enhance Bcl-2 and interferone tau gene expression, which may result in a net increase in viability in bovine embryos.

Pluripotent embryonic stem (ES) cells differentiate spontaneously into beating cardiomyocytes via embryo-like aggregates. We describe the use of mouse embryonic stem (mES03) cells as a reproducible differentiation system for cardiomyocyte. To induce cardiomyocytic differentiation, mES03 cells were dissociated and allowed to aggregate (EB formation) at the presence of 0 75% dimethyl sulfoxide (DMSO) for 4 days and then another 4 days without DMSO (4+/4-). Thus treated EBs were plated onto gelatin-coated dish for differentiation. Spontaneously contracting colonies which appeared in approximately 4-5 days upon differentiation. Expression of cardiac-specific genes were determined by RT-PCR. Rebust expression of myosin light chain (MLC-2V), cardiac myosin heavy chain , cardiac muscle heavy polypeptide 7 -MHC), cardiac transcription factor GATA4 and skeletal muscle-specific -subunit of the L-type calcium channel () were detected as early as 8 days after EB formation, but message of cardiac muscle-specific -subunit of the L-type calcium channel (CaCh) were revealed at a low level. Strikingly, the expression of atrial natriuretic factor (ANF) was not detected. When spontaneous contracting cell masses were examined their electrophysiological features by patch-clamp technique, it showed ventricle-like action potential 17 days after the EB formation. This study indicates that mES03 cell-derived cardiomyocytes displayed biochemical and electrophysiological properties of cardiomyocytes and DMSO enhanced development of cardiomyocytes in 4+/4- method.

Epidermal growth factor (EGF) induces well-documented mitegenic and differentiating effects on murine and bovine preimplantation embryos. However, the effects of EGF on apoptosis and implantation-related gene expression in bovine embryos developing in vitro have not been evaluated. The objective of this study was to determine the effects of exogenous EGF in the presence and absence of BSA on the preimplantation development of bovine embryos. In addition, we measured cell number, apoptosis, and expression of apoptosis and implantation-related genes of the blastocysts that developed in these culture conditions. In vitro produced bovine embryos were randomly cultured in the same medium containing 0 or 10 ng/ EGF in the presence and absence of 0.8% BSA. More 2-cell embryos developed into blastocysts at day 7 when BSA was present than when BSA was absent. The addition of 10 ng/ EGF into the medium did not significantly increase the developmental rate and the cell numbers per blastocyst. However, addition of EGF in the presence of 0.8% BSA significantly reduced the degree of apoptosis in the blastocysts (P< 0.01). To investigate whether EGF modulates mRNA expression of apoptosis-related genes, mRNA was prepared from single blastocysts and each preparation was subjected to RT-PCR for Bcl-2 and Bax transcripts. EGF did not alter the relative abundance of Bax gene expression in the presence of BSA, but increase Bcl-2 (P < 0.01). The relative abundance of Interferon tau expression was increased by EGF treatment in the presence of BSA. These results suggest that EGF and BSA synergistically enhance Bcl-2 and interferone tau gene expression, which may result in a net increase in viability in bovine embryos.

Recently, human embryonic stem (hES) cells have become very important resources for ES cell basic research, cell replacement therapy, and other medical applications; thus, efficient cryopreservation methods for these cells are needed. This study examined whether a newly developed minimum volume cooling (MVC) vitrification method, which was tested through cryopreservation of sensitive bovine oocytes, can be used for freezing hES cells. Feeder-free cultured hES cell (MB03) colonies were mechanically dissected into several small clumps following enzymatic treatment. We compared the freezing efficiency of a slow-cooling method using a cryo-module (0.4-0.6C/min, 20-30 clumps/vial) and MVC vitrification using a modified 0.5-ml French mini-straw designated as a MVC straw (>/min, 10 clumps/straw) After thawing, in vitro survival of hES cell clumps was higher for MVC-vitrified cells (80.8%, 97/120) than for slow-cooled cells (38.2%, 39/102). Further, the proliferation rate of surviving MVC-vitrified cells was similar to that of control hES cells from 2 weeks after thawing. In addition, vitrified-thawed hES cells demonstrated a normal karyotype, were positively immunostained for surface marker antibodies (AP, SSEA-4 and TRA-1-60) and the Oct-4 antibody, and could differentiate into all three embryonic germ layer cells in vitro. This result demonstrates that hES cell clumps can be successfully cryopreserved by a newly developed MVC vitrification method without loss of human cell characteristics.