The purposes of this study were to determine whether the naturally occurring flavonoid quercetin, as its glucorhamnoside rutin, reduces intestinal permeability and susceptibility to hypoxia-induced pulmonary hypertension in neonatal Holstein calves. A 2 × 2 between-subjects factorial design was conducted using Holstein steers (n = 16). Factors included oxygen level (simulated altitude of 4,572 m vs. 975 m) and quercetin supplementation as its glucorhamnoside rutin (4 g of quercetin per day vs. 0 g per day). Two days after arrival (d 0 of study) the calves were blocked by body mass into treatment groups, and treatments were initiated. Pulmonary arterial pressure, echocardiography, and serum concentrations of orally administered lactulose (0.45 g/kg) and mannitol (0.15 g/kg) were measured on d 12, 13, and 14, respectively. Calves were euthanized on d 15 and pulmonary tissues collected for semiquantitative scoring of histological lesions. Data were analyzed using linear regression, generalized estimating equations, and 2-sample proportion tests. Hypoxia, but not rutin, was found to be associated with intestinal permeability. The lactulose-mannitol ratio was 0.54 ± 0.13 (standard error) in hypoxic calves and 0.02 ± 0.13 in normoxic controls. Hypoxia increased mean pulmonary arterial pressure. Calves fed rutin under hypoxic conditions tended to have a lower mean pulmonary arterial pressure (59 ± 7 mmHg) than control calves (80 ± 7 mmHg) but similar pressures under normoxic conditions. Paradoxically, however, a greater proportion of calves fed rutin had histological evidence of pulmonary arteriolar medial hypertrophy and adventitial hyperplasia than did controls. In conclusion, the findings of this study indicate that hypoxia increased intestinal permeability in neonatal calves. The flavonoid quercetin, as its glucorhamnoside rutin, had no protective effect on intestinal permeability, and, although it tended to reduce the severity of hypoxia-induced pulmonary hypertension, a greater proportion of calves fed rutin had histological lesions consistent with pulmonary arteriolar remodeling.

中文翻译：

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尽管喂养了类黄酮芦丁，但低氧会导致新生荷斯坦牛犊的肠道通透性增加和肺动脉压力增加。

这项研究的目的是确定天然存在的类黄酮槲皮素作为其糖原鼠李糖苷芦丁是否能降低肠道渗透性和对新生儿荷斯坦牛犊低氧引起的肺动脉高压的敏感性。使用荷斯坦牛（n = 16）进行了2×2受试者间析因设计。影响因素包括氧气水平（模拟海拔4,572 m与975 m）和槲皮素的葡糖鼠李糖苷芦丁补充量（每天4 g槲皮素vs.每天0 g）。到达后两天（研究的第0天），小牛被体重阻塞进入治疗组，并开始治疗。分别在第12、13和14天分别测定口服乳果糖（0.45 g / kg）和甘露醇（0.15 g / kg）的肺动脉压，超声心动图和血清浓度。在第15天对小牛实施安乐死，并收集肺组织用于组织学病变的半定量评分。使用线性回归，广义估计方程和2样本比例检验对数据进行分析。缺氧，但不是芦丁，与肠道通透性有关。低氧犊牛的乳果糖-甘露醇比率为0.54±0.13（标准误），而正常氧对照组的乳果糖-甘露醇比率为0.02±0.13。缺氧会增加平均肺动脉压。低氧条件下饲喂芦丁的牛的平均肺动脉压（59±7 mmHg）低于对照牛犊（80±7 mmHg），但在常氧条件下的压力相似。然而，自相矛盾的是，与对照组相比，饲喂芦丁的小牛的组织学证据显示肺小动脉内侧肥大和外膜增生。总之，这项研究的结果表明缺氧会增加新生牛犊的肠道通透性。类黄酮槲皮素作为其鼠李糖苷类芦丁，对肠道通透性没有保护作用，尽管它倾向于减轻缺氧引起的肺动脉高压的严重性，但饲喂芦丁的犊牛组织学病变与肺小动脉重塑一致。