Institute for Fetology, First Hospital of Soochow University, Suzhou, China.
Perenatology Laboratory, Maternal and Child Health Care Hospital of Wuxi, Wuxi, China.
Hypertens Res. 2022 Jul;45(7):1168-1182. doi: 10.1038/s41440-022-00935-y. Epub 2022 May 18.
Hypoxia can lead to adult middle cerebral artery (MCA) dysfunction and increase the risk of cerebrovascular diseases. It is largely unknown whether intrauterine hypoxia affects fetal MCA vasodilatation. This study investigated the effects and mechanisms of intrauterine hypoxia on fetal MCA vasodilatation. Near-term fetal sheep were exposed to intrauterine hypoxia. Human umbilical vein endothelial cells (HUVECs) were exposed to hypoxia in cellular experiments. Vascular tone measurement, molecular analysis, and transmission electron microscope (TEM) were utilized to determine vascular functions, tissue anatomy, and molecular pathways in fetal MCA. In fetal MCA, acetylcholine (ACh) induced reliable relaxation, which was markedly attenuated by intrauterine hypoxia. Atropine, P-F-HHSiD, L-NAME, and u0126 blocked most ACh-mediated dilation, while AF-DX 116 and tropicamide partially inhibited the dilation. Indomethacin and SB203580 did not significantly change ACh-mediated dilation. Tempol and PS-341 could restore the attenuated ACh-mediated vasodilatation following intrauterine hypoxia. The mRNA expression levels of CHRM2 and CHRM3 and the protein levels of CHRM3, p-NOS3, SOD2, ERK1/2, p-ERK1/2, MAPK14, and p-MAPK14 were significantly reduced by intrauterine hypoxia. The dihydroethidium assay showed that the production of ROS was increased under intrauterine hypoxia. TEM analysis revealed endothelial cells damaged by intrauterine hypoxia. In HUVECs, hypoxia increased ROS formation and decreased the expression of CHRM3, p-NOS3, SOD1, SOD2, SOD3, ERK1/2, p-ERK1/2, and p-MAPK14, while tempol and PS-341 potentiated p-NOS3 protein expression. In conclusion, in utero hypoxia reduced ACh-mediated vasodilatation in ovine MCA predominantly via decreased CHRM3 and p-NOS3, and the decreased NOS3 bioactivities might be attributed to ROS and ERK1/2.
缺氧可导致成年大脑中动脉（MCA）功能障碍，增加脑血管疾病的风险。目前尚不清楚宫内缺氧是否会影响胎儿 MCA 血管舒张。本研究旨在探讨宫内缺氧对胎儿 MCA 血管舒张的影响及机制。将近足月胎儿羊置于宫内缺氧环境中，在细胞实验中用缺氧处理人脐静脉内皮细胞（HUVEC）。采用血管张力测量、分子分析和透射电镜（TEM）检测胎儿 MCA 的血管功能、组织解剖和分子途径。在胎儿 MCA 中，乙酰胆碱（ACh）诱导可靠的舒张，宫内缺氧明显减弱了这种舒张。阿托品、P-F-HHSiD、L-NAME 和 u0126 阻断了大部分 ACh 介导的舒张，而 AF-DX 116 和托吡卡胺部分抑制了舒张。吲哚美辛和 SB203580 对 ACh 介导的舒张没有明显影响。Tempol 和 PS-341 可恢复宫内缺氧后减弱的 ACh 介导的血管舒张。宫内缺氧后，CHRM2 和 CHRM3 的 mRNA 表达水平以及 CHRM3、p-NOS3、SOD2、ERK1/2、p-ERK1/2、MAPK14 和 p-MAPK14 的蛋白水平均显著降低。二氢乙啶测定显示宫内缺氧时 ROS 生成增加。TEM 分析显示宫内缺氧可损伤内皮细胞。在 HUVEC 中，缺氧增加了 ROS 的生成，降低了 CHRM3、p-NOS3、SOD1、SOD2、SOD3、ERK1/2、p-ERK1/2 和 p-MAPK14 的表达，而 Tempol 和 PS-341 增强了 p-NOS3 蛋白的表达。综上所述，宫内缺氧通过降低 CHRM3 和 p-NOS3 降低了胎儿 MCA 中 ACh 介导的血管舒张，NOS3 生物活性的降低可能归因于 ROS 和 ERK1/2。
