Abstract：
The equine uterus is highly interrogated during estrus prior to breeding and establishing pregnancy. Many studies in mares have been performed during estrus under the influence of high estrogen concentrations, including the equine estrual microbiome. To date, it is unknown how the uterine microbiome of the mare is influenced by cyclicity; while, the equine vaginal microbiome is stable throughout the estrous cycle. We hypothesized that differences would exist between the equine endometrial microbiome of mares in estrus and anestrus. The aim of this study was two-fold: to characterize the resident endometrial microbiome of healthy mares during anestrus and to compare this with estrus. Double-guarded endometrial swabs were taken from healthy mares during estrus (n = 16) and in the following non-breeding season during anestrus (n = 8). Microbial population was identified using 16S rRNA sequencing. Our results suggest that the equine uterine microbiome in estrus has a low diversity and low richness, while during anestrus, a higher diversity and higher richness were seen compared to estrus. Despite this difference, both the estrus and anestrus endometrial microbiome were dominated by Proteobacteria, Firmicutes, and Bacteroidota. The composition of the microbial community between anestrus and estrus was significantly different. This may be explained by the difference in the composition of the endometrial immune milieu based on the stage of the cycle. Further research investigating the function of the equine endometrial microbiome and dynamics changes within the uterine environment is required.
摘要：
马子宫在繁殖和怀孕之前的发情期受到高度询问。在高雌激素浓度的影响下，发情期对母马进行了许多研究，包括马的祖先微生物组。迄今为止,目前尚不清楚母马的子宫微生物组如何受到周期性的影响；而，马阴道微生物组在整个发情周期中是稳定的。我们假设发情期和发情期的马子宫内膜微生物组之间存在差异。这项研究的目的是双重的：表征暴动期间健康母马的子宫内膜微生物组，并将其与发情期进行比较。在发情期（n=16）和随后的非繁殖季节（n=8）从健康的母马中取出双重保护的子宫内膜拭子。使用16SrRNA测序鉴定微生物群体。我们的结果表明，发情期的马子宫微生物组具有低多样性和低丰富度，而在暴动期间，与发情相比，发现了更高的多样性和更高的丰富度。尽管有这种差异,发情期和发情期子宫内膜微生物组均以变形杆菌为主，Firmicutes,和拟杆菌。发情期和发情期之间的微生物群落组成差异显著。这可以通过基于周期阶段的子宫内膜免疫环境的组成差异来解释。需要进一步研究马子宫内膜微生物组的功能和子宫环境内的动态变化。
