Influences of somatic donor cell sex on and embryo development following somatic cell nuclear transfer in pigs.

Objective: The present study investigates pre- and post-implantation developmental competence of nuclear-transferred porcine embryos derived from male and female fetal fibroblasts.

Methods: Male and female fetal fibroblasts were transferred to -matured enucleated oocytes and and developmental competence of reconstructed embryos was investigated. And, a total of 6,789 female fibroblast nuclear-transferred embryos were surgically transferred into 41 surrogate gilts and 4,746 male fibroblast nuclear-transferred embryos were surgically transferred into 25 surrogate gilts.

The effects of artificial activation timing on the development of SCNT-derived embryos and newborn piglets.

This study investigated the effects of two different activation regimens on the developmental potential of somatic cell nuclear transfer (SCNT) embryos and postnatal survivability of the cloned piglets. In vitro matured oocytes were enucleated and reconstructed with porcine fetal fibroblasts. On the basis of the activation regimen used, the reconstructed porcine embryos were allocated into two groups: Group 1-simultaneous electrical pulses and activation group (SFA group); and Group 2-electrical fusion without calcium followed by electrical pulses with calcium after colcemid and cytochalasin B treatment for 5h (DA group).

Electrical activation enhances pre-implantation embryo development following sperm injection into in vitro matured pig oocytes.

The objective of this study was to evaluate the effect of electrical stimulation (EST) on pronuclear formation, chromosomal constitution, and developmental capability among in vitro matured pig oocytes following intracytoplasmic sperm injection (ICSI). After ICSI, the oocytes were randomly distributed and cultured into 3 groups: the EST activated ICSI group, non-activation ICSI group, and in vitro fertilization (IVF) group. The proportion of oocytes in which 2 pronuclei were formed in ICSI groups was significantly higher in the former groups than in the IVF group (96.

Histone deacetylase inhibition improves activation of ribosomal RNA genes and embryonic nucleolar reprogramming in cloned mouse embryos.

Our group found that the treatment of embryos with histone deacetylase inhibitors (HDACi), including trichostatin A, Scriptaid, suberoylanilide hydroxamic acid, and oxamflatin, after cloning by somatic cell nuclear transfer (SCNT) resulted in significantly improved efficiency. Although many researchers have investigated the use of HDACi treatment to improve the quality of cloned mouse embryos, the mechanism underlying this treatment has not been completely understood. We believe that the effect of HDACi on embryonic gene activation (EGA) is important for normal development of cloned embryos.

Developmental arrest of scNT-derived fetuses by disruption of the developing endometrial gland as a result of impaired trophoblast migration and invasiveness.

Somatic cell nuclear transfer (scNT)-derived pig placenta tissues of gestational day 30 displayed avascularization and hypovascularization. Most of the cytotrophoblast-like cells of the developing scNT-derived placenta villi were improperly localized or exhibited impaired migration to their targeting loci. Id-2, Met, MMP-9, and MCM-7 were barely detectable in the cytotrophoblast cells of the scNT-derived placenta villi.

Osmolarity at early culture stage affects development and expression of apoptosis related genes (Bax-alpha and Bcl-xl) in pre-implantation porcine NT embryos.

This study examined whether high osmolarity of culture medium at the early culture stage affects development and expression of apoptosis related genes (Bax-alpha and Bcl-xl) of porcine nuclear transfer (NT) and in vitro fertilization (IVF) embryos. NT and IVF embryos were divided into three groups and the basic medium was PZM-3 (260-270 mOsmol, control group). The control group of embryos was cultured in PZM-3 for whole culture period.

A rare and often unrecognized cerebromeningitis and hemodynamic disorder: a major cause of sudden death in somatic cell cloned piglets.

In this study, we generated 40 somatic cell cloned (scNT) piglets. Of these, five piglets were stillborn, 22 scNT piglets died suddenly within the first week of life, and 1 piglet died after 40 days. Twelve scNT piglets are still healthy.

Detection of rare Leydig cell hypoplasia in somatic cell cloned male piglets.

In this investigation, 22 cloned male piglets were obtained by male fetal fibroblast-cell-derived nuclear transfer. Eighteen of the cloned animals died. The two cell lines did not differ significantly with regard to efficiency of live piglet production.