Laboratory of Animal Reproduction, Department of Biological Sciences, Biomaterials Research Cluster, Bernal Institute, Faculty of Science and Engineering, University of Limerick, Limerick, Ireland.
Teagasc Animal & Grassland Research and Innovation Centre, Grange, Dunsany, Co. Meath, Ireland.
Theriogenology. 2021 Dec;176:26-34. doi: 10.1016/j.theriogenology.2021.09.012. Epub 2021 Sep 20.
Some bulls with apparently normal semen quality yield unacceptably low pregnancy rates. We hypothesised that a differential uterine immunological response to sperm from high and low fertility bulls may contribute to these differences. The experimental model used was heifer follicular phase uterine explants incubated with frozen-thawed sperm from high and low fertility bulls (3-5 replicates per experiment). Inflammatory gene expression of IL1A, IL1B, IL6, TNFA and CXCL8 were assessed by qPCR and IL1-β and IL-8 were quantified in explant supernatants by ELISA. Neutrophil binding affinity to sperm from high and low fertility bulls was also assessed. There was a significant up-regulation of IL1A, IL1B and TNFA from frozen-thawed sperm, irrespective of fertility status, compared to the unstimulated control. This response was confirmed at the protein level, with an increase of IL-1β and IL-8 protein concentrations by 5 and 2.7 fold, respectively (P < 0.05). Although no significant differences in the inflammatory response at the gene or protein level were evident between high and low fertility bulls, more sperm from low compared to high fertility bulls bound to neutrophils (P < 0.05). Using bulls of unknown fertility, cauda epididymal sperm (CES) plus seminal plasma (SP) upregulated IL6 (P < 0.05) but there was no upregulation of any inflammatory gene expression for CES alone. Overall, this ex vivo study demonstrated an upregulation of inflammatory gene expression in the uterus in response to frozen-thawed bull sperm. While there was no difference between sperm from high and low fertility bulls, there was a greater binding affinity of low fertility sperm by neutrophils.
一些精液质量看似正常的公牛，其受胎率却低得令人无法接受。我们假设，对高、低繁殖力公牛精子的子宫免疫反应的差异可能导致了这些差异。使用的实验模型是在发情期牛的子宫外植体中培养冷冻-解冻的高、低繁殖力公牛精子（每个实验 3-5 个重复）。通过 qPCR 评估白细胞介素 1A、白细胞介素 1B、白细胞介素 6、肿瘤坏死因子α和 CXCL8 的炎症基因表达，并通过 ELISA 定量测定外植体上清液中的白细胞介素 1-β和白细胞介素 8。还评估了高、低繁殖力公牛精子对中性粒细胞的结合亲和力。与未刺激对照相比，无论繁殖力状态如何，冷冻解冻的精子都显著上调了白细胞介素 1A、白细胞介素 1B 和肿瘤坏死因子α。这一反应在蛋白质水平得到了证实，IL-1β和 IL-8 蛋白浓度分别增加了 5 倍和 2.7 倍（P<0.05）。尽管高、低繁殖力公牛之间在基因或蛋白质水平上的炎症反应没有明显差异，但与高繁殖力公牛相比，更多的低繁殖力公牛精子与中性粒细胞结合（P<0.05）。使用未知繁殖力的公牛，尾附睾精子（CES）加精浆（SP）上调了白细胞介素 6（P<0.05），但 CES 单独没有任何炎症基因表达的上调。总的来说，这项离体研究表明，冷冻解冻的公牛精子会引起子宫内炎症基因表达的上调。虽然高、低繁殖力公牛精子之间没有差异，但低繁殖力精子与中性粒细胞的结合亲和力更强。
