Male disadvantage? Fetal sex and cardiovascular responses to asphyxia in preterm fetal sheep
Male disadvantage? Fetal sex and cardiovascular responses to asphyxia in preterm fetal sheep
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DOI：
10.1152/ajpregu.00342.2007
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发表时间：
2007-09-01
影响因子：
2.8
通讯作者：
Gunn, Alistair J.
中科院分区：
文献类型：
--
作者：
Bennet, Laura;Booth, Lindsea C.;Gunn, Alistair J.
临床和实验表明，男性胎儿在出生时死亡或受伤的风险明显更大，特别是在早产后。我们对60只雌性和65只雄性单胎早产胎羊（103 - 104天，妊娠0.7天）进行了回顾性队列分析，在子宫内脐带闭塞25分钟期间记录了平均动脉血压（MAP）、心率以及颈动脉和股动脉血流。如果胎儿MAP低于8 mmHg或如果心搏停止> 20 s，则早期停止闭塞。能够完成完整25分钟闭塞期的胎仔显示，任何心血管反应在性别间无差异。男性（平均：21分钟，n = 16）和女性（平均：23分钟，n = 16）中早期停止闭塞的数量相似;然而，它们显示出不同的反应。与完全闭塞胎仔相比，短闭塞雄性（n = 16）显示股血管电导的初始下降较慢，随后出现更严重的心动过缓、低血压和相关器官灌注不足。相比之下，短闭塞雌性（n = 16）显示股血管传导性的早期增加比完全闭塞胎仔显著更快，随后心动过缓和低血压恶化介于完全闭塞胎仔和短闭塞雄性之间。在所有胎儿中，MAP在15分钟的闭塞，对应的时间下降的最大速率，与死后的体重在男性（R-2 = 0.07），但不是女性。总之，男性和女性胎儿表现出显着相似的化学反射和血流动力学反应，严重窒息，但一些男性在正常体重范围内表现出受损的血流动力学适应。
Clinically and experimentally male fetuses are at significantly greater risk of dying or suffering injury at birth, particularly after premature delivery. We undertook a retrospective cohort analysis of 60 female and 65 male singleton preterm fetal sheep ( 103 - 104 days, 0.7 gestation) with mean arterial blood pressure ( MAP), heart rate, and carotid and femoral blood flow recordings during 25 min of umbilical cord occlusion in utero. Occlusions were stopped early if fetal MAP fell below 8 mmHg or if there was asystole for > 20 s. Fetuses that were able to complete the full 25- min period of occlusion showed no differences between sexes for any cardiovascular responses. Similar numbers of occlusions were stopped early in males ( mean: 21 min, n = 16) and females ( mean: 23 min, n = 16); however, they showed different responses. Short- occlusion males ( n = 16) showed a slower initial fall in femoral vascular conductance, followed by greater bradycardia, hypotension, and associated organ hypoperfusion compared with full- occlusion fetuses. In contrast, short- occlusion females ( n = 16) showed a significantly more rapid early increase in femoral vascular conductance than the full- occlusion fetuses, followed by worsening of bradycardia and hypotension that was intermediate to the full- occlusion fetuses and short- occlusion males. Among all fetuses, MAP at 15 min of occlusion, corresponding with the time of the maximal rate of fall, was correlated with postmortem weight in males ( R-2 = 0.07) but not females. In conclusion, male and female fetuses showed remarkably similar chemoreflex and hemodynamic responses to severe asphyxia, but some males did show impaired hemodynamic adaptation within the normal weight range.