外泌体在日粮纤维调控猪母-胎界面血管生成及胚胎附植中的作用

胚胎附植是影响胚胎存活及产仔数的重要限制因素，母-胎界面血管生成对于胚胎附植至关重要。课题组前期研究发现，妊娠期饲喂适宜水平或来源纤维改善胎儿均匀度及产仔数。研究表明，日粮纤维影响妊娠母猪繁殖激素分泌，而人类医学研究发现，繁殖激素调控输卵管和子宫外泌体的分泌，且外泌体通过影响血管生成因子调控多种重要器官功能；然而，纤维能否通过子宫液外泌体途径影响母-胎界面血管生成进而影响胚胎附植，尚不清楚。本项目首先通过分离妊娠早期母猪子宫液外泌体考察日粮纤维对外泌体分泌的影响、母-胎界面血管生成和胚胎发育；在此基础上，通过妊娠早期母猪活体注射日粮纤维处理母猪来源的子宫液外泌体，考察母-胎界面血管生成、胚胎附植和胚胎发育，揭示外泌体介导日粮纤维改善母-胎界面血管生成的机制。研究结果对阐明日粮纤维调控胚胎附植期血管生成的分子机制具有重大理论意义，并对显著提高母猪繁殖力具有重要的实践价值。

Embryo implantation is the primary limiting factor affecting fetal survival and litter size. The angiogenesis at the maternal-fetal interface during the pre-implantation phase plays a crucial role in embryo implantation. Our previous studies found that the appropriate dietary fiber level and the ratio of soluble and insoluble fiber improve fetal uniformity and increase the litter size in sows. It has been found that dietary fiber affect the reproductive hormone secretion in pregnant sows. The human medical studies have found that reproductive hormones regulate the secretion of fallopian tubes and uterine exosomes. Exosomes regulate multiple important organ functions by affecting angiogenic factors. However, it remains largely unclear whether the uterine fluid exosome could be changed by dietary fiber, which in turn mediate the effects of dietary fiber on the angiogenesis of embryo maternal-fetal interface, thus improve the embryo implantation. In this project, we will first investigate the effect of dietary fiber on exosome secretion, angiogenesis at the maternal-fetal interface, and embryo development by isolating the exosomes and embryos from sow uterine fluid and uterine in early pregnancy. Then, exosome injection will be used in vivo in early pregnancy sow to further investigate the effects of exosome from dietary fiber treatment on the angiogenesis at the maternal-fetal interface, embryo implantation and embryo development. The results of this project will disclosure the molecular mechanism of dietary fiber regulating angiogenesis during embryonic implantation, and have important practical value for improving the reproductive potential of sow.