Concentrations of progesterone prior to luteolysis modulates the uterine luminal transcriptome in the subsequent cycle in cattle

Sex-steroids concentrations throughout the estrous cycle modulate endometrial function and fertility in cattle. The objective of this study was to compare the post-estrus endometrial transcriptome of cows that were exposed to contrasting pre-estrus concentrations of progesterone before they displayed estrus and ovulated spontaneously. We hypothesized that greater pre-estrus concentration of progesterone alters post-estrus endometrial function even after the display of estrus and spontaneous ovulation. Overall design: Bos indicus-influenced cross-bred beef cows exposed to either high (H) or low (L) pre-estrus concentrations of progesterone. On day -9, the cows assigned to the high progesterone treatment received a new CIDR and 2 mL GnRH i.m. while the cows assigned to low progesterone treatment received a CIDR used twice previously, 5 mL PGF2a i.m. and 2 mL GnRH i.m. Ovarian ultrasonography and blood collections were performed on d -9, d -2, d -0.5, d 0 (observed estrus), d 4, d 7, and d 14 for measurement of ovarian structures, progesterone, and estradiol. Luminal epithelial cells were collected using a cytology brush on d 4, d 7, and d 14 for RNA-sequencing analysis.

发情周期内的性激素浓度可调控牛子宫内膜功能与生育能力。本研究旨在对比：在自发发情并排卵前，暴露于不同浓度孕酮（Progesterone）的母牛，其发情后子宫内膜转录组的差异。本研究提出假设：即使在发情表现与自发排卵完成后，较高的发情前孕酮浓度仍会改变发情后子宫内膜功能。实验整体设计：选取受印度瘤牛（Bos indicus）血统影响的杂交肉牛，分为高浓度（H组）与低浓度（L组）发情前孕酮处理两组。在第-9天，高孕酮处理组母牛植入全新的阴道孕酮释放装置（CIDR），并肌内注射2 mL促性腺激素释放激素（Gonadotropin-Releasing Hormone, GnRH）；低孕酮处理组母牛则植入已使用两次的CIDR，同时肌内注射5 mL前列腺素F2α（Prostaglandin F2α, PGF2α）与2 mL GnRH。分别在第-9天、第-2天、第-0.5天、第0天（观察到发情）、第4天、第7天及第14天开展卵巢超声检查与血液采集，用于检测卵巢结构、孕酮、雌二醇（Estradiol）水平。分别于第4天、第7天与第14天使用细胞刷采集子宫内膜腔上皮细胞，进行RNA测序（RNA-sequencing）分析。