Pifithrin-α ameliorates resveratrol-induced two-cell block in mouse preimplantation embryos in vitro

FoxO transcription factors 1 regulate mouse preimplantation embryo development

PURPOSE

The aim of the present study is to investigate role of FoxO transcription factors in preimplantation embryo development by knocking down FoxO1, FoxO3, and FoxO4 genes and also to assess cell cycle arrest related proteins, p53 and p21, and apoptosis-related proteins, fas ligand (FASL), and cleaved caspase 3.

METHODS

Knockdown of FoxOs using siRNA was confirmed utilizing RT-PCR and qRT-PCR in gene level and using immunofluorescence in protein level. Following knockdown of FoxO1, FoxO3, and FoxO4 in two-cell mouse embryos with or without resveratrol treatment; developmental competence of embryos and expression patterns of SIRT1, p53, p21, FASL, and CLEAVED CASPASE 3 proteins in embryos by immunofluorescence were assessed after 48 h. ROS levels were measured in knockdown embryos. Terminal deoxynucleotidyl transferase dUTP nick end labeling assay was used to determine resveratrol dose.

RESULTS

Successful knockdown of FoxO genes in mouse embryos utilizing a non-invasive siRNA method was achieved. Significantly, knockdown of FoxO genes impaired preimplantation embryo development which cannot be prevented by resveratrol treatment. Immunofluorescence results showed that resveratrol could protect embryos from cell cycle arrest and apoptosis. FOXO proteins regulate apoptosis and cell cycle related proteins in mouse preimplantation embryos. Moreover, there might be an autofeedback mechanism where FOXO1, FOXO3, and FOXO4 regulate SIRT1 protein expression.

CONCLUSIONS

These results suggest that FOXO transcription factors could contribute to mouse preimplantation embryo development, and it remains to investigate whether they have crucial roles in human preimplantation embryo and infertility.

Resveratrol addition to in vitro maturation and in vitro culture media enhances developmental competence of sheep embryos

The present study aimed to examine the effects of adding different concentrations of resveratrol during in vitro culture (IVC) alone and during both in vitro maturation (IVM) and IVC on ovine blastocyst yield and quality. Therefore, this study was conducted in two separate experiments. The first experiment was carried out to test the effect of different concentrations of resveratrol (0, 0.1, 0.25, 0.5, 2.0, and 5.0 μM) in the IVC medium on cleavage, morula, developmental potential of blastocyst, and total cell number (TCN) of the embryos. Addition of 0.25 and 0.5 μM of resveratrol during IVC significantly enhanced morula and blastocyst rates as compared with other groups (P < 0.05). Also, supplementation of the IVC medium with 0.5 μM of resveratrol had beneficial effects on trophectoderm cells (TE), inner cell mass (ICM), and TCN of blastocysts. In the second experiment, the same concentrations of resveratrol (0, 0.1, 0.25, 0.5, 2.0, and 5.0 μM) were applied during IVM and IVC. Therefore, oocytes were matured in vitro in the presence of different concentrations of resveratrol for 22-24 h. After in vitro fertilization, presumptive zygotes were cultured in media containing 0, 0.1, 0.25, 0.5, 2.0, and 5.0 μM of resveratrol for 8 d. No significant difference was found in the percentage of oocytes developed to MII (0, 0.1, 0.25, 0.5, and 2.0 μM of resveratrol), but the percentage of oocytes developed to MII were significantly lower in 5.0 μM of resveratrol in comparison with other groups. Addition of 0.5 μM of resveratrol to the maturation and culture media significantly increased morula and blastocyst rates compared with other groups (P < 0.05). However, a too high concentration of resveratrol (5.0 μM) during IVM and IVC decreased cleavage, morula, and blastocyst rates compared with low concentrations (P < 0.05). Treatment with 0.5/0.5 μM of resveratrol during IVM/IVC significantly improved the TE, ICM, and TCN of blastocysts. In conclusion, sequential treatment with 0.5 μM of resveratrol during IVM and IVC and during IVC alone improved the developmental competence of oocytes, which was reflected in higher blastocyst rates and TCN of blastocysts.

Function of berberine on porcine in vitro fertilization embryo development and differential expression analysis of microRNAs

The effect of berberine (Ber) on in vitro fertilization (IVF) embryo development in pigs and the associated differential expression of microRNAs (miRNAs) in the embryo were investigated. NCSU-23 embryonic culture medium was used for a control group, while NCSU-23 embryonic culture medium added with Ber was used for a Ber group. The embryo development rates in these groups were determined, and the zygotes, 4- and 8-cell embryos, and blastocysts were collected for cDNA microarray analysis. The development rates of 2-, 4-, 8-cell embryos and blastocysts were significantly higher in the Ber group than those in the control group (p < 0.01). The differentially expressed miRNAs in the 8-cell versus the 4-cell stage in control group as well as in the 8-cell Ber group versus the 8-cell control group overlapped, and it was found that nine miRNAs were commonly upregulated and two of them were downregulated, while there was no overlap among the other groups. The target genes of Ber-regulated miRNAs at the 8-cell stage were mainly associated with the molecular pathway of nucleic acid and protein synthesis. These findings suggest that Ber may regulate the expression of miRNAs at the 8-cell stage, which is beneficial to provide material reserves for the maternal to zygote transition of porcine embryos, thereby increasing the porcine IVF embryo development rate.

Effect of potential role of p53 on embryo development arrest induced by H2O2 in mouse

During mammalian embryo development in vitro, mechanism of embryonic development arrest caused by oxidative stress has not been clear so far. The tumor suppressor protein p53 controls cell cycle and programmed cell death by regulating relevant signal pathway. Recent researches revealed that the concentration and distribution of p53 are closely related with reactive oxygen species (ROS). The main objective of this experiment was to explore the role of p53 on embryonic development arrest caused by oxidative stress. Results showed that embryo arrest at two-four-cell stage was significantly increased in the presence of 50 μM H₂O₂ (39.01 ± 2.74 vs. 77.20 ± 5.34%, p < 0.05). Supplementation of N-acetyl-L-cysteine (NAC) obviously reduced the ratio of development arrest (39.01 ± 2.74 vs. 71.18 ± 5.34%, p < 0.05), which was accompanied by an increase in ROS level, and H₂O₂ treatment sharply increased messenger RNA (mRNA) expression and protein levels of p53 and p53-ser15. Further increased transcription of GADD45a and p21, a downstream of p53, has an especially significant effect on the mRNA expression of GADD45a. However, expressions of cdc2 were reduced by H₂O₂. In addition, using Pifithrin-α (PFT-α), the suppresser of p53, the result showed that GADD45a and p21 were significantly downregulated, but the cell cycle gene cdc2 was significantly upregulated, while the protein level of p53 and p53-ser15 was significantly decreased. Taken together, these results demonstrate that ROS could activate p53 and regulate p53 target genes to influence early embryo development in in vitro culture.