Our objectives were to investigate potential changes in the size of steroidogenic large luteal cells (LLC) during partial luteolysis induced by a sub-dose of cloprostenol in early diestrus and to determine transcriptional variations in genes involved in corpus luteum (CL) functions. Cows were subjected to an Ovsynch protocol, with the time of the second GnRH treatment defined as Day 0 (D0). On D6, cows were randomly allocated into three treatments: Control (2 mL saline, im; n = 10), 2XPGF (two doses of 500 μg of cloprostenol, im, 2 h apart; n = 8) or 1/6PGF (single dose of 83.3 μg of cloprostenol, im; n = 10). Before treatments and every 8 h during the 48-h experimental period, blood samples were collected and CL volumes measured. Furthermore, two CL biopsies were obtained at 24 and 40 h post-treatment. The 1/6PGF treatment caused partial luteolysis, characterized by sudden decreases in plasma progesterone (P4) concentrations, luteal volume and LLC size, followed by increases (to pretreatment values) in P4 and luteal volume at 24 and 40 h post-treatment, respectively. However, at the end of the study, P4, luteal volume and LLC size were all significantly smaller than in Control cows. Temporally associated with these phenotypes, there was a lower mRNA abundance of VEGFA at 24 and 40 h, and ABCA1 at 24 h (P < 0.05). In conclusion, a sudden reduction in CL size during partial luteolysis induced by a sub-dose of PGF2α analog on day 6 of the estrous cycle was attributed to a reduction in LLC size, although these changes did not account for the entire phenomenon. In addition to its involvement in reducing CL size, decreased VEGFA mRNA abundance impaired CL development, resulting in a smaller luteal gland and lower plasma P4 concentrations compared to Control cows.

中文翻译：

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牛早期发情期间的部分黄体溶解下调 VEGFA 表达并减少大黄体细胞和黄体大小。和血浆孕酮浓度

我们的目标是研究在早期发情期亚剂量氯前列醇诱导的部分黄体分解过程中类固醇​​生成大黄体细胞 (LLC) 大小的潜在变化，并确定参与黄体 (CL) 功能的基因的转录变异。奶牛接受 Ovsynch 协议，第二次 GnRH 治疗的时间定义为第 0 天 (D0)。在第 6 天，奶牛被随机分配到三个处理组：对照（2 mL 生理盐水，im；n = 10）、2XPGF（两剂 500 μg 氯前列醇，im，间隔 2 小时；n = 8）或 1/6PGF（单次剂量为 83.3 μg 氯前列醇，im；n = 10)。在治疗前和 48 小时实验期间每 8 小时收集一次血样并测量 CL 体积。此外，在治疗后 24 和 40 小时获得了两次 CL 活检。1/6PGF 治疗导致部分黄体溶解，其特征是血浆孕酮 (P4) 浓度、黄体体积和 LLC 大小突然降低，随后分别在治疗后 24 和 40 小时 P4 和黄体体积增加（至治疗前值） . 然而，在研究结束时，P4、黄体体积和 LLC 大小都明显小于对照奶牛。与这些表型暂时相关的是，在 24 和 40 小时时 VEGFA 的 mRNA 丰度较低，在 24 小时时 ABCA1 的 mRNA 丰度较低（P < 0.05）。总之，在发情周期的第 6 天，由亚剂量 PGF2α 类似物诱导的部分黄体溶解期间 CL 大小突然减小归因于 LLC 大小的减小，尽管这些变化并不能解释整个现象。除了参与减少 CL 的大小，