Abnormal placental angiogenesis is associated with the occurrence of intrauterine growth restriction (IUGR) in piglets, and effective treatment strategies against this occurrence remain to be explored. Adenosine has been reported to play an important role in angiogenesis, but its role in placental angiogenesis is still unknown. Here, we investigated the effect of dietary adenosine supplementation on IUGR occurrence in piglets by analyzing the role of adenosine in placental angiogenesis for Normal and IUGR piglets. Specifically, 88 sows were allotted to 2 treatments (n = 44) and fed a basal diet supplemented with 0% or 0.1% of adenosine from day 65 of gestation until farrowing, followed by collecting the placental samples of Normal and IUGR piglets, and recording their characteristics. The results showed that adenosine supplementation increased the mean birth weight of piglets (P < 0.05) and placental efficiency (P < 0.05), while decreasing the IUGR piglet rate (P < 0.05). Expectedly, the placenta for IUGR neonates showed a down-regulated vascular density (P < 0.05) and angiogenesis as evidenced by the expression level of vascular cell adhesion molecule-1 (VCAM1) (P < 0.05). Notably, dietary adenosine supplementation promoted angiogenesis (P < 0.05) both in the Normal and IUGR placenta. More importantly, the expression level of adenosine A2a receptor (ADORA2A) was lower (P < 0.05) in the IUGR placenta than in Normal placenta, whereas adenosine treatment could significantly increase ADORA2A expression, and also had an interaction effect between factors IUGR and Ado. Collectively, placentae for IUGR piglets showed impaired angiogenesis and down-regulated expression level of ADORA2A, while dietary adenosine supplementation could activate ADORA2A expression, improve the placental angiogenesis, and ultimately decrease the occurrence of IUGR in piglets.

胎盘血管生成异常与仔猪宫内生长受限（IUGR）的发生有关，针对这种情况的有效治疗策略仍有待探索。据报道，腺苷在血管生成中起重要作用，但其在胎盘血管生成中的作用仍然未知。在这里，我们通过分析腺苷在正常和 IUGR 仔猪胎盘血管生成中的作用，研究了膳食补充腺苷对仔猪 IUGR 发生的影响。具体而言，88 头母猪被分配到 2 个处理组（n = 44) 并从妊娠 65 天至分娩饲喂添加 0% 或 0.1% 腺苷的基础日粮，随后采集正常和 IUGR 仔猪的胎盘样本，并记录它们的特征。结果表明，添加腺苷可提高仔猪的平均出生体重（P  < 0.05）和胎盘效率（P  < 0.05），同时降低 IUGR 仔猪率（P  < 0.05）。正如预期的那样，IUGR 新生儿的胎盘显示出下调的血管密度 ( P  < 0.05) 和血管生成，如血管细胞粘附分子-1 (VCAM1) 的表达水平所证明的 ( P  < 0.05)。值得注意的是，膳食补充腺苷促进血管生成（P < 0.05) 在正常和 IUGR 胎盘中。 更重要的是，IUGR 胎盘中腺苷 A2a 受体（ADORA2A）的表达水平低于正常胎盘（P < 0.05），而腺苷处理可显着增加 ADORA2A 的表达，并且 IUGR 和 Ado 因子之间存在交互作用。总的来说，IUGR 仔猪的胎盘表现出血管生成受损和 ADORA2A 表达水平下调，而日粮补充腺苷可以激活 ADORA2A 表达，改善胎盘血管生成，最终减少仔猪 IUGR 的发生。