Vasileva Anastasiia, Flores Laura D M, Vasilyev Mikhail, Buckman Michelle A, DeRuisseau Lara R, Tomasson Michael H, Bates Melissa L
Department of Health and Human Physiology, University of Iowa, Iowa City, Iowa, United States.
Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States.
Am J Physiol Regul Integr Comp Physiol. 2025 Jan 1;328(1):R133-R144. doi: 10.1152/ajpregu.00097.2024. Epub 2024 Dec 5.
Urethane is widely used for its ability to induce prolonged anesthesia. Variability in previously reported cardiovascular parameters in murine models makes it challenging to definitively evaluate the cardiovascular effects of urethane anesthesia. We aimed to address these challenges, thereby advancing our understanding of urethane's effects on cardiovascular function in mice. In this study, we investigated how urethane anesthesia, with and without supplemental oxygen, impacts heart rate, arterial oxygen saturation ([Formula: see text]), blood pressure, and heart rate variability in mice. First, we conducted a literature review and found that data in mice were both limited and lacking in reproduction. Next, we conducted a series of physiological measurements to address gaps in the literature and subjected C57BL/6J mice to three conditions: ) conscious, ) urethane-anesthetized, and ) urethane-anesthetized with supplemental oxygen. Blood pressure, heart rate, [Formula: see text], and heart rate variability (via time, frequency, and M-curve analyses) were assessed. We observed an increase in heart rate with urethane anesthesia ( = 0.012) compared with the conscious state. Urethane caused a decrease in heart rate variability, which was independent of oxygen supplementation. Urethane anesthesia caused a significant reduction in arterial blood pressure ( < 0.001) with oxygen-supplemented mice remained hypotensive. Urethane decreased [Formula: see text] ( = 0.001), which was restored by oxygen supplementation ( < 0.001). We did not observe sex effects of urethane anesthesia on blood pressure, heart rate, heart rate variability, or [Formula: see text]. Taken together, these results underscore the importance of a cautious approach when using urethane in mice, as urethane significantly impacts arterial blood pressure, heart rate, oxygen saturation, and heart rate variability. This investigation documents cardiovascular outcomes in mice receiving urethane anesthesia, emphasizing sex as a biological variable, and considering oxygen supplementation during anesthesia. This is the first report of M-curve analysis in rodents as a heart rate-independent variability analysis.
乌拉坦因其能诱导长时间麻醉而被广泛使用。先前报道的小鼠模型中心血管参数的变异性使得明确评估乌拉坦麻醉对心血管的影响具有挑战性。我们旨在应对这些挑战，从而增进我们对乌拉坦对小鼠心血管功能影响的理解。在本研究中，我们调查了有无补充氧气的乌拉坦麻醉如何影响小鼠的心率、动脉血氧饱和度（[公式：见正文]）、血压和心率变异性。首先，我们进行了文献综述，发现小鼠方面的数据既有限又缺乏可重复性。接下来，我们进行了一系列生理测量以填补文献中的空白，并将C57BL/6J小鼠置于三种条件下：）清醒状态，）乌拉坦麻醉状态，以及）补充氧气的乌拉坦麻醉状态。评估了血压、心率、[公式：见正文]和心率变异性（通过时间、频率和M曲线分析）。我们观察到与清醒状态相比，乌拉坦麻醉使心率增加（ = 0.012）。乌拉坦导致心率变异性降低，这与是否补充氧气无关。乌拉坦麻醉使动脉血压显著降低（ < 0.001），补充氧气的小鼠仍处于低血压状态。乌拉坦使[公式：见正文]降低（ = 0.001），补充氧气可使其恢复（ < 0.001）。我们未观察到乌拉坦麻醉对血压、心率、心率变异性或[公式：见正文]有性别影响。综上所述，这些结果强调了在小鼠中使用乌拉坦时采取谨慎方法的重要性，因为乌拉坦会显著影响动脉血压、心率、血氧饱和度和心率变异性。本研究记录了接受乌拉坦麻醉的小鼠的心血管结局，强调性别作为一个生物学变量，并考虑麻醉期间的氧气补充。这是首次在啮齿动物中进行M曲线分析作为一种与心率无关的变异性分析的报告。
