Effects of a postnatal high-salt diet on cardiac function in offspring from hypoxic pregnancies

Prenatal hypoxia is a common pregnancy complication that can permanently alter the structure and function of the fetal heart and predispose individuals to cardiovascular disease. However, the interactive effects of prenatal hypoxia and postnatal lifestyle choices are poorly studied. This study investigated the combined effects of prenatal hypoxia and a postnatal high-salt diet on cardiac function in adulthood. Pregnant Wistar rats were exposed to either 21% oxygen (normoxic group, n = 8) or 10.5% oxygen (hypoxic group, n = 8) from day 15-20 of gestation. Male offspring were divided into two groups at 5 weeks of age; normal salt (0.3 % NaCl) and high salt (8% NaCl) chow. Blood pressure and echocardiography measurements were performed at 18 weeks to assess cardiovascular function. Rats from hypoxic pregnancies had pulmonary hypertension and right ventricular thickening; whereas rats fed a postnatal high-salt diet had systemic hypertension, left ventricular wall thickening, and a reduced myocardial performance index. When prenatal hypoxia was combined with a postnatal high-salt diet, the rats exhibited a combination of the two phenotypes, but there were no significant interactions. Results suggest postnatal diet can worsen cardiovascular outcomes in offspring from hypoxic pregnancies, which can have significant implications for disease management.

产前缺氧是一类常见妊娠并发症，可永久性改变胎儿心脏的结构与功能，增加个体日后罹患心血管疾病的风险。然而，产前缺氧与产后生活方式选择的交互效应尚未得到充分研究。本研究旨在探究产前缺氧联合产后高盐饮食对成年个体心脏功能的复合影响。选取妊娠Wistar大鼠，于妊娠第15至20天分别暴露于21%氧气（常氧组，n=8）与10.5%氧气（缺氧组，n=8）环境。待雄性子代大鼠生长至5周龄时，将其分为两组，分别喂食正常盐（0.3%氯化钠）与高盐（8%氯化钠）饲料。于大鼠18周龄时开展血压与超声心动图（echocardiography）检测，以评估其心血管功能。产前缺氧妊娠组的子代大鼠出现肺动脉高压与右心室肥厚；而产后喂食高盐饮食的子代大鼠则表现为系统性高血压、左心室壁肥厚及心肌性能指数降低。当产前缺氧与产后高盐饮食联合干预时，子代大鼠同时呈现上述两种表型，但未观察到显著的交互效应。本研究结果提示，产后饮食可恶化产前缺氧妊娠子代的心血管预后，该发现对心血管疾病的临床管理具有重要参考价值。