The purposes of this study were to examine technical details in deriving and maintaining rabbit embryonic stem (rES) cell lines and to analyze their characteristics. When STO cells were used as feeder cells, no rES cell lines were established using either intact blastocysts or inner cell masses (ICMs). On the mouse embryonic fibroblasts (MEF) feeder, rES cell lines were efficiently (24%) derived. Addition of leukemia inhibitory factor (LIF) to the cells cultured on the MEF feeders further increased the derivation efficiency (57%) of rES cells. The fact that LIF induced serine-phosphorylation of STAT3 suggested LIF-dependent maintenance of rES cells. Most of the rES cell lines expressed AP, SSEA-4, Oct4, TRA-1-60, and TRA-1-81. Western blot or RT-PCR analysis also confirmed the expression of Oct4, Nanog, and Sox2. When induced to form EBs in vitro or injected to the severe combined immunodeficiency (SCID) mice, the rES cells generated embryoid bodies (EBs) and teratomas with three germ layers expressing the marker genes including MAP2, Desmin, and GATA4, respectively. In conclusion, rabbit ES cell lines can be efficiently established using our current protocols with LIF supplement. These ES cells express pluripotent stem cell markers and retain their capability to differentiate into different tissue cells. Furthermore, rES cells depend on LIF for self-renewal, likely via the JAK-STAT pathway.

Our results for the murine model provide direct scientific evidence that mitochondrial transfer improves embryonic development. However, potential risks such as mitochondrial heteroplasmy, nuclear-mitochondrial interaction and epigenetic aspects all deserve further evaluation before mitochondrial transfer is applied clinically.

These data suggest that oral estrogen induces ASVD risk by increasing acute inflammation; however, transdermal estrogen avoids this untoward effect. Additionally, transdermal estrogen exerts a positive effect on endothelial function similar to that of oral estrogen. Therefore, the transdermal route might be favourable in terms of ASVD risks.

The preincubation of oocytes for at least 2.5 h is beneficial to both IVF and ICSI outcomes by increasing the nuclear maturity of oocytes.

The CLBRs in the study group were significantly higher than those in the control group (64.3% vs. 45.8%, p = 0.001). Subgroup analysis revealed that when the number of oocyte pick up (OPU) is between 4 and 15, the CLBRs in the study group were significantly better (58.3% vs. 40.9%, p = 0.042). For those with OPU <4 or OPU >15 the CLBRs were similar in these two groups (OPU < 4: study vs. control 23.1% vs. 18.8% respectively, p = 0.713; OPU>15: study vs. control 85.7% vs. 80.8% respectively, p = 0.625) CONCLUSION: The Freeze-all policy improved the ART outcome for normal responders.