Hoffman F, Boretto E, Vitale S, Gonzalez V, Vidal G, Pardo M F, Flores M F, Garcia F, Bagnis G, Queiroz O C M, Rabaglino M B
National Scientific and Technical Research Council (CONICET), Argentina.
Department of Animal Reproduction, College of Agronomy and Veterinary, National University of Río Cuarto, Argentina.
Theriogenology. 2018 Mar 1;108:331-338. doi: 10.1016/j.theriogenology.2017.12.023. Epub 2017 Dec 15.
Maternal nutritional restrictions during late gestation could lead to fetal hypoglycemia. Glucose levels in the fetal sheep regulate circulating insulin-like growth factor 1 (IGF1) levels, which stimulate cell proliferation and differentiation of reproductive organs after binding to its own receptor or estrogen receptors. The objective of this study was to determine the effects of subnutrition of ewes during the last trimester of gestation on the serum glucose/IGF1 levels and development of reproductive organs in their lambs. Pregnant ewes carrying singletons were randomly assigned to restricted (R ewes, n = 8) or control (C ewes, n = 8) groups (4 lambs of each gender/group) and fed with 50% or 100% of metabolic energy requirements from ∼100 days of gestation to term (∼147 days), respectively. Blood samples from lambs were taken on the first day after born and once at week for serum glucose and IGF1 determination. Lambs were euthanatized at 2 months of age, reproductive organs were weighted and tissue samples were collected from them for histology and to measure mRNA expression of IGF1 and its receptor (IGF1R) by qRT-PCR. Pre-partum glucose levels in R ewes were significantly lower compared to C ewes (p < .05). Compared to lambs born from C ewes, lambs born from R ewes showed lower serum levels of glucose and IGF1 during the first week of age (p < .05). At 2 month of age, these lambs had significant lower uterine and testicular weight and lower ovarian, uterine and testicular mRNA expressions of IGF1 and its receptor (p < .05). Histological findings showed that diameter of secondary and tertiary follicles in ovaries and number of endometrial glands in uterus of females, or number of Sertoli cells and seminiferous tubules and diameter, perimeter and tubular area in testicles of males were significantly lower in lambs born from R ewes compared to the respective organs of lambs born from the C ewes (p < .05). In conclusion, these results demonstrate that maternal subnutrition during late gestation affects IGF1 levels during fetal life and impairs reproductive development in the neonatal lamb, which could have permanent negative consequences in the future reproductive performance of the offspring.
妊娠后期母体营养限制可能导致胎儿低血糖。胎羊的葡萄糖水平调节循环中的胰岛素样生长因子1（IGF1）水平，IGF1与自身受体或雌激素受体结合后，可刺激生殖器官的细胞增殖和分化。本研究的目的是确定妊娠最后三个月母羊营养不足对其羔羊血清葡萄糖/IGF1水平及生殖器官发育的影响。将怀有单胎的妊娠母羊随机分为限制组（R组母羊，n = 8）和对照组（C组母羊，n = 8）（每组各性别4只羔羊），分别在妊娠约100天至足月（约147天）期间给予代谢能量需求的50%或100%的饲料。在羔羊出生后第一天采集血样，并每周采集一次，用于测定血清葡萄糖和IGF1。羔羊在2月龄时安乐死，称取生殖器官重量，并采集组织样本进行组织学检查，通过qRT-PCR测量IGF1及其受体（IGF1R）的mRNA表达。与C组母羊相比，R组母羊产前葡萄糖水平显著降低（p < 0.05）。与C组母羊所生羔羊相比，R组母羊所生羔羊在出生后第一周血清葡萄糖和IGF1水平较低（p < 0.05）。在2月龄时，这些羔羊的子宫和睾丸重量显著降低，卵巢、子宫和睾丸中IGF1及其受体的mRNA表达也较低（p < 0.05）。组织学结果显示，与C组母羊所生羔羊的相应器官相比，R组母羊所生羔羊卵巢中次级和三级卵泡直径、子宫中子宫内膜腺体数量，或雄性睾丸中支持细胞和生精小管数量以及直径、周长和管状面积均显著降低（p < 0.05）。总之，这些结果表明，妊娠后期母体营养不足会影响胎儿期的IGF1水平，并损害新生羔羊的生殖发育，这可能对后代未来的繁殖性能产生永久性负面影响。
