Department of Immunology and Pathology of Reproduction, Institute of Animal Reproduction and Food Research of Polish Academy of Sciences, 10-748 Olsztyn, Poland.
Department of Basic and Preclinical Sciences, Institute for Veterinary Medicine, Nicolaus Copernicus University, 87-100 Torun, Poland.
Cells. 2021 Oct 5;10(10):2661. doi: 10.3390/cells10102661.
Worldwide, dairy cows of the type of high-producing cattle (HPC) suffer from health and fertility problems at a young age and therefore lose productivity after an average of only three lactations. It is still contentious whether these problems are primarily due to genetics, management, feeding or other factors. Vascularization plays a fundamental role in the cyclic processes of reproductive organs, as well as in the regeneration of tissues. In a previous study, HPC were shown to have a greater ovarian corpus luteum vascularization compared to dual-purpose breeds. We hypothesize that this activated angiogenesis could likely lead to an early exhaustion of HPC's regenerative capacity and thus to premature reproductive senescence. The objective of this study was to investigate if a HPC breed (Holstein-Friesian, HF) exhibits higher ovarian angiogenesis than a dual-purpose breed (Polish Red cow, PR) and if this is related to early ovarian aging and finally reproductive failure. For this purpose, we assessed the degree of vascularization by means of ovarian blood vessel characterization using light microscopy. As indicators for aging, we measured ovarian mitochondrial size and telomere length in peripheral leukocytes. We report in this study that in both breeds the distance between capillaries became smaller with increasing age and that the mean telomere length decreased with increasing age. The only difference between the two breeds was that PR developed larger capillaries than HF. Neither a relationship between telomere length, nor the morphology of the mitochondrial apparatus and nor angiogenesis in HF was proven. Although the data trends indicated that the proportion of shortened telomeres in HF was higher than in the PR, no significant difference between the two breeds was detected.
在全球范围内，高产奶牛（HPC）类型的奶牛在年轻时就会出现健康和生育问题，因此在平均仅三次泌乳后就会失去生产力。这些问题主要是由于遗传、管理、饲养还是其他因素造成的，仍然存在争议。血管生成在生殖器官的周期性过程以及组织再生中起着根本作用。在之前的一项研究中，与兼用品种相比，HPC 具有更大的卵巢黄体血管化。我们假设这种激活的血管生成可能导致 HPC 的再生能力过早耗尽，从而导致生殖早衰。本研究的目的是调查 HPC 品种（荷斯坦弗里森，HF）是否比兼用品种（波兰红牛，PR）表现出更高的卵巢血管生成，以及这是否与早期卵巢衰老和最终生殖失败有关。为此，我们使用光学显微镜通过卵巢血管特征评估血管生成程度。作为衰老的指标，我们测量了外周白细胞中的卵巢线粒体大小和端粒长度。我们在本研究中报告说，在两个品种中，随着年龄的增长，毛细血管之间的距离变小，端粒长度随着年龄的增长而减小。两个品种之间唯一的区别是 PR 比 HF 形成更大的毛细血管。HF 中的端粒长度、线粒体装置的形态或血管生成之间没有证明存在相关性。尽管数据趋势表明 HF 中短端粒的比例高于 PR，但两个品种之间没有检测到显著差异。
