França Moana Rodrigues, da Silva Maressa Izabel Santos, Pugliesi Guilherme, Van Hoeck Veerle, Binelli Mario
Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, 225, Duque de Caxias Norte Ave. Jd. Elite, 13635-900 Pirassununga, SP Brazil.
Gamete Research Centre, University of Antwerp, Antwerp, Belgium.
J Anim Sci Biotechnol. 2017 Jun 15;8:54. doi: 10.1186/s40104-017-0185-1. eCollection 2017.
In beef cattle, changes in the periovulatory endocrine milieu are associated with fertility and conceptus growth. A large preovulatory follicle (POF) and the resulting elevated concentrations of progesterone (P4) during diestrus positively affect pregnancy rates. Amino acids (AA) are important components of maternally derived secretions that are crucial for embryonic survival before implantation. The hypothesis is that the size of the POF and the concentration of P4 in early diestrus modulate the endometrial abundance of SLC transcripts related to AA transport and metabolism and subsequently impact luminal concentrations of AA. The follicle growth of Nelore cows was manipulated to produce two experimental groups: large POF and CL (LF-LCL group) and small POF and CL (SF-SCL group). On Day 4 (D4; Experiment 1) and Day 7 (D7; Experiment 2) after GnRH-induced ovulation (GnRH treatment = D0), the animals were slaughtered and uterine tissues and uterine washings were collected. qRT-PCR was used to evaluate the expression levels of AA transporters in D4 and D7 endometrial tissues. The concentrations of AA were quantified in D4 and D7 uterine washings by HPLC.
Transcript results show that, on D4, and and on D7 and were more abundant in the endometria of cows from the LF-LCL group ( < 0.05). In addition, concentrations of AA in the uterine lumen were influenced by the endocrine profiles of the mother. In this context, D4 uterine washings revealed that greater concentrations of taurine, alanine and α-aminobutyric acid were present in SF-SCL ( < 0.05). In contrast, lower concentrations of valine and cystathionine were quantified on D7 uterine washings from SF-SCL cows ( < 0.05).
The present study revealed an association between the abundance of transcripts related to AA transport and metabolism in the endometrium and specific periovulatory endocrine profiles related to the receptive status of the mother. Such insights suggest that AAs are involved in uterine function to support embryo development.
在肉牛中，排卵前后内分泌环境的变化与生育能力和孕体生长有关。排卵前大卵泡（POF）以及随后在发情间期孕酮（P4）浓度升高对妊娠率有积极影响。氨基酸（AA）是母体分泌物的重要组成部分，对植入前胚胎存活至关重要。假说是，发情早期POF的大小和P4浓度调节与AA转运和代谢相关的SLC转录本在子宫内膜中的丰度，随后影响管腔中AA的浓度。对Nellore母牛的卵泡生长进行调控，以产生两个实验组：大POF和黄体（LF-LCL组）以及小POF和黄体（SF-SCL组）。在GnRH诱导排卵后第4天（D4；实验1）和第7天（D7；实验2）（GnRH处理= D0），宰杀动物并收集子宫组织和子宫冲洗液。采用qRT-PCR评估D4和D7子宫内膜组织中AA转运体的表达水平。通过HPLC对D4和D7子宫冲洗液中的AA浓度进行定量。
转录结果显示，在D4时，以及在D7时，LF-LCL组母牛子宫内膜中的和更丰富（<0.05）。此外，子宫管腔中AA的浓度受母体内分泌特征的影响。在这种情况下，D4子宫冲洗液显示，SF-SCL组中牛磺酸、丙氨酸和α-氨基丁酸的浓度更高（<0.05）。相反，在SF-SCL组母牛的D7子宫冲洗液中，缬氨酸和胱硫醚的浓度较低（<0.05）。
本研究揭示了子宫内膜中与AA转运和代谢相关的转录本丰度与母体接受状态相关的特定排卵前后内分泌特征之间的关联。这些见解表明，AA参与子宫功能以支持胚胎发育。
