RESUMEN
The purpose of this study was to evaluate the efficiency of intracytoplasmic sperm injection [ICSI] and Piezo-assisted sperm injection after pretreatment with calcium ionophore [CaI] on the mouse embryo development. In this study, the conventional ICSI and Piezo-ICSI procedures were used. The efficacy of the methods was examined after mouse matured oocytes were fertilized with or without CaItreated sperms. Piezo-ICSI demonstrated significantly more favorable results, with a fertilization rate of 64% [conventional ICSI: 42%, P<0.001] and a cleavage rate of 73% [conventional ICSI: 58%, P<0.05]. When the Piezo-ICSI procedure was performed with CaI-pretreated sperms, the cleavage rate significantly increased [92% vs. 73%, P<0.05]. However, the fertilization rate did not change significantly [64% vs. 56%]. The Piezo-ICSI accompanies with CaI-treated sperms is more efficient than the conventional ICSI method for fertilizing and thus obtaining more mouse embryos
RESUMEN
Human embryonic stem cells [hESC], which are derived from the inner cell mass of the blastocysts, have been considered to be pluripotent cells. In this study we examine the differentiating potential of hESC into hepatocytes by characterization of the expression of endoderm and liver-specific genes. hESC were cultivated in suspension to form aggregates, the embryoid bodies. They were allowed to outgrowth on the plated culture with the stepwise addition of growth factors such as acidic fibroblast growth factor [aFGF], hepatocyte growth factor and oncostatin M into the culture medium. The expressions of endodermal and liver specific genes such as hepatocyte nuclear factor 3 beta, alpha-fetoprotein [AFP], albumin [ALB], cytokeratin 8 [CK-8], CK-18, transthyretin, glucose 6-phosphatase and tyrosine aminotransferase were analyzed by reverse transcription-polymerase chain reaction [RT-PCR]. The expressions of ALB and CK-18 in the cytoplasm were analyzed by Immunohistochemistry. The immunoblotting and chemiluminescence of the conditioned media indicated the secretion of ALB and AFP. RT-PCR analysis revealed that hepatic gene expression related to early and late-stage liver development were enhanced through in vitro differentiation of hESC. Our results showed the expression of endoderm and hepatic specific genes after in vitro differentiation of hESC into hepatocyte-like cells through addition of various growth factors in three dimensional culture systems [collagen type I]. hESC could be a new potential source of hepatocyte for transplantation in patients with liver failure