ABSTRACT
Objective To explore whether superovulation impairs the process of pregnancy establishment in mice by changing the intrauterine environment. Methods The implantation and pregnancy of superovulated and normal mice were compared. The superovulated mice were subjected to unilateral tubal ligation on day 0. 5 and blastocysts were transplanted to the other uterine horn on day 2. 5. The number of implantation sites of bilateral uterine horn was compared. The differences between preimplantation uteri of superovulated and normal pseudopregnancy mice were compared by tissue sections and high-throughput sequencing. Bioinformatics analysis was performed on the differentially expressed genes in two groups. Results Compared with the control group, the pregnancy rate of mice in the superovulation group decreased significantly. The number of implantation sites in the superovulation group was higher than the control. There was no significant difference in the pregnancy rate of the uterine horn between the control side and the transplanted side of the superovulated mice. The endometrium was thinned and the number of glands was reduced in superovulated pseudopregnancy mice. The gene expression patterns of preimplantation uterus in superovulation pseudopregnancy and normal pseudopregnancy mice were different. There were 1097 significantly differentially expressed genes, including 752 up-regulated genes and 345 down-regulated genes. Bioinformatics analysis showed that differentially expressed genes are mainly involved in biological processes, such as decidualization, response to progesterone, positive regulation of angiogenesis. They were mainly enriched in FoxO signaling pathway, cell cycle pathway and steroid biosynthesis pathway. Conclusion Superovulation impaired the process of establishing pregnancy and altered the gene expression patterns of biomarker of uterine receptivity in mice.
ABSTRACT
Objective To investigate the role of inner cell mass (ICM) in decidualization using decidua induced by two-cell embryos or tetraploid embryos through tubal embryo transfer. Methods Tetraploid embryo, as the inner cell mass-deficient embryo, were produced by electrofusion of mouse 2-cell embryos. Decidua was induced by 2-cell embryos or tetraploid embryos through tubal embryo transfer. Decidua induced by 2-cell embryos was employed as a control. Morphologic and implantation site of decidua were compared between two-cell embryo-induced decidua and tetraploid embryo-induced decidua. The differentially expressed microRNA ( miRNA ) was screened by high-throughput sequencing. The target genes of differentially expressed miRNA in two groups were screened for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Results Tetraploid embryo-induced decidual tissue and 2-cell embryo- induced decidual tissue were very similar at the implantation site, but there were significant differences in decidual morphology. There were 16 miRNAs differentially expressed in decidua of the two groups, of which 11 miRNAs (miR-466f- 3p, miR-302 d-3p, miR-466i-5p, miR-465c-5p, miR-302a-5p, miR-7068-3p, miR-741-3p, miR-302a-3p, miR-433-5p, miR-144-5p, miR-878-5p) were up-regulated in tetraploid embryo-induced decidua and 5 miRNAs (miR-690, miR-193b- 5p, miR-147-3p, novel_327, miR-363-3p) were down-regulated in tetraploid embryo-induced decidua. Bioinformatics analysis showed that the target genes played function such as protein binding and ion binding, and mainly involved in cyclic guanosine monophosphate-protein kinase G (cGMP-PKG) signaling pathway, estrogen signaling pathway, vascular endothelial growth factor (VEGF) signaling pathway and so on. Conclusion ICM plays an important role in decidualization.