Relationships among the corpus luteum, follicles and conceptus in sheep

Ultrasonography for the detection of pregnancy and study of embryonic and fetal development in camels, buffaloes, and sheep: Techniques, equations, and limitations

New technologies for detecting pregnancy shortly after mating/insemination and identifying gestational age are essential for speeding up the reproductive cycle and ensuring high reproductive efficiency in livestock farming. Ultrasonography can successfully identify pregnancy and determine gestational age in many domestic animals. On the other hand, many herds of camel and buffalo and flocks of sheep are aware of the day of service, making it difficult to appropriately manage pregnant animals. This study provides a review of the literature on various techniques for ultrasonographically diagnosing pregnancy in camels, buffaloes, and sheep, focusing on the most appropriate times to use each technique, the earliest opportunity to diagnose pregnancy, and the possibility of using various parts of the fetus to create mathematical equations to determine gestational age. Some limitations of ultrasonography in pregnancy diagnosis were identified and significant pregnancy events in dromedaries were discussed, including left-horn and twin pregnancies. The data presented here will prove essential for researchers, farmers, and countries that rely heavily on these animals for providing meat, milk, cosmetics, and other animal products to enhance reproduction and production efficiency.

PPARγ regulates lipid metabolism and viability of sheep trophoblast cells

Peroxisome proliferator-activated receptor γ (PPARγ) is highly expressed in trophoblast tissues in pregnancy during which the protein participates in diverse events, including embryo implantation and placental formation. However, little is known about the role of PPARγ in embryonic development. This study investigated the function of PPARγ in sheep trophoblast cells. The coding sequence of sheep PPARγ encoded 475 amino acids and included one synonymou mutation compared with the sheep reference sequence for PPARγ. The PPARγ protein was localized in the nucleus and cytoplasm of sheep trophoblasts. The relative expression of PPARγ was elevated in cells treated with rosiglitazone and reduced following administration of GW9662. Activation of PPARγ promoted cell proliferation and mobility, but inhibited apoptosis. In addition, stimulation of PPARγ promoted the expression of lipid metabolism-related genes FABP4 and PLIN2. The expression of prostaglandin metabolism-related genes PLA2G4A, PTGS2 and PTGES also was upregulated significantly in trophoblast cells when PPARγ was activated. In contrast, activation of PPARγ did not impact expression of the prostaglandin-related genes PGFS and SLCO2A1. At the same time, activation of PPARγ activity increased the ratio of PGE2 to PGF2α. Furthermore, fluorescence labelling showed that the numbers of cell lipid droplets increased after stimulation of PPARγ activity, but decreased when PPARγ was inhibited. In conclusion, PPARγ is critical for the regulation of lipid metabolism and prostaglandin synthesis and secretion in sheep trophoblast cells and also has a potent effect on cell proliferation and viability.

The transcriptome-wide N6-methyladenosine (m6A) map profiling reveals the regulatory role of m6A in the yak ovary

BACKGROUND AND AIM

Yak estrus is a seasonal phenomenon, probably involving epigenetic regulation of synthesis and secretion of sex hormones as well as growth and development of follicles. N6-methyladenosine (m⁶A) is the most common internal modification of the eukaryotic mRNA. However, there are no detailed reports on the m⁶A transcriptome map of yak ovary. Therefore, this study aimed to collected the yak ovarian tissues at three different states of anestrus (YO-A), estrus (YO-F), and pregnancy (YO-P), and obtained the full transcriptome m⁶A map in yak by MeRIP-seq.

RESULTS

The HE staining revealed that the number of growing follicles and mature follicles in the ovary during the estrus period was relatively higher than those in the anestrus period and the pregnancy period. The RT-qPCR showed that the expression of METTL3, METTL14, FTO, YTHDC1 were significantly different across different periods in the ovaries, which suggests that m⁶A may play a regulatory role in ovarian activity. Next, we identified 20,174, 19,747 and 13,523 m⁶A peaks in the three ovarian samples of YO-A, YO-F and YO-P using the methylated RNA immunoprecipitation sequencing (MeRIP-seq). The m⁶A peaks are highly enriched in the coding sequence (CDS) region and 3'untranslated region (3'UTR) as well as the conserved sequence of "RRACH." The GO, KEGG and GSEA analysis revealed the involvement of m⁶A in many physiological activities of the yak's ovary during reproductive cycle. The association analysis found that some genes such as BNC1, HOMER1, BMP15, BMP6, GPX3, and WNT11 were related to ovarian functions.

CONCLUSIONS

The comparison of the distribution patterns of methylation peaks in the ovarian tissues across different periods further explored the m⁶A markers related to the regulation of ovarian ovulation and follicular development in the yak ovary. This comprehensive map provides a solid foundation for revealing the potential function of the mRNA m⁶A modification in the yak ovary.