Effect Of Timed Artificial Insemination On Uterine Development Of Gilts In Early Pregnancy And Screening And Identification Of Differential MiRNAs

Timed artificial insemination?TAI?technology is of great significance for improving the utilization rate of gilt breeding,reducing non-production days,and organizing batch production.In order to explore the mechanism of the influence of TAI procedures on the reproductive performance of gilts,this study selected 12 healthy gilts,divided into treatment group?T?and control group?C?.T group was treated with altrenogest+GnRH+PMSG,C group was not treated with hormones.Gilts were slaughtered on the 16th and 25th days of pregnancy.Endometrial tissues were collected as research objects,and were recorded as T₁6 group?n=3?,C₁6 group?n=3?,T₂5 group?n=3?,C₂5 group?n=3?.First observe the morphological changes of the endometrium,and then perform high-throughput sequencing of the endometrium at the site of implantation to obtain the miRNA expression profile.By comparing the differences in tissue development and miRNA expression to explore the mechanism of TAI influencing the reproductive performance of gilts.The main results are as follows:TAI procedures have an effect on endometrial thickness,microvessels and glandular development.Compared with the C group,Whether it is the 16th or 25th day of pregnancy,the endometrial thickness of the gilts in the T group increased,the blood vessels were denser and richer,the glands developed more developed,and they were more evenly distributed in the lamina propria.These changes were more conducive to the attachment of early embryos.Through high-throughput sequencing of the endometrial tissues of gestational gilts,the expression profile of endometrial miRNAs were established.Analysis of the sequencing results screened the following differential miRNA related to reproduction:ssc-miR-142?ssc-miR-141?ssc-miR-10383?ssc-miR-424.Among them,the expression levels of ssc-miR-10383 and ssc-miR-424 were up-regulated,and the expression levels of ssc-miR-142 and ssc-miR-141 were down-regulated.Those miRNAs were preliminarily identified by qRT-PCR test.Using GO and KEGG enrichment analysis to analyze the differentially expressed miRNA target genes,it was found that these differentially expressed miRNAs participate in the immune and cell function related pathways through the target genes to achieve the regulation of embryo implantation.According to the NCBI database,the target genes COP1 and CX3CL1 of miR-424 were screened and confirmed to be differentially expressed in the uterus of gilts.The expression levels of COP1 and CX3CL1 in the endometrium of gilts in the T group were significantly lower than those in the C group?P<0.05?.This indicates that ssc-miR-424 can target COP1 and CX3CL1 genes in the gilt uterus in early pregnancy.It indicates that TAI up-regulates the expression of ssc-miR-424 and participates in the regulation of embryo implantation during early pregnancy by targeting the gene expression of CX3CL1.In summary,this experiment shows that the treatment of TAI procedure promotes the development of the uterus of the gilts in early pregnancy and is beneficial to the attachment of early embryos.The miRNAs that were differentially expressed in the endometrium of the T group and the C group were screened,and it was confirmed that the treatment of TAI could upregulate the expression of ssc-miR-424 in the endometrium,and then down regulate the expression of the target gene CX3CL1 to participate in the regulation of embryo attachment.