Department of Clinical Pharmacology, University Medical Center Groningen, The Netherlands.
J Leukoc Biol. 2013 Sep;94(3):431-7. doi: 10.1189/jlb.0611298. Epub 2013 Jun 13.
Hibernation consists of periods of low metabolism, called torpor, interspersed by euthermic arousal periods. During deep and daily (shallow) torpor, the number of circulating leukocytes decreases, although circulating cells, is restored to normal numbers upon arousal. Here, we show that neutropenia, during torpor, is solely a result of lowering of body temperature, as a reduction of circulating also occurred following forced hypothermia in summer euthermic hamsters and rats that do not hibernate. Splenectomy had no effect on reduction in circulating neutrophils during torpor. Margination of neutrophils to vessel walls appears to be the mechanism responsible for reduced numbers of neutrophils in hypothermic animals, as the effect is inhibited by pretreatment with dexamethasone. In conclusion, low body temperature in species that naturally use torpor or in nonhibernating species under forced hypothermia leads to a decrease of circulating neutrophils as a result of margination. These findings may be of clinical relevance, as they could explain, at in least part, the benefits and drawbacks of therapeutic hypothermia as used in trauma patients and during major surgery.
冬眠由代谢率较低的时期（称为蛰伏期）组成，其间穿插着体温正常的觉醒期。在深度和日常（浅层）蛰伏期间，循环白细胞的数量减少，尽管在觉醒时循环细胞恢复到正常数量。在这里，我们表明，在蛰伏期间中性粒细胞减少仅是体温降低的结果，因为在不冬眠的夏季恒温仓鼠和大鼠中，强制低温后也会发生循环中性粒细胞减少。脾切除术对蛰伏期间循环中性粒细胞减少没有影响。中性粒细胞向血管壁的边缘聚集似乎是导致低温动物中性粒细胞数量减少的机制，因为用地塞米松预处理可抑制该作用。总之，自然使用蛰伏或在强制低温下的非冬眠物种中较低的体温导致循环中性粒细胞减少，这是由于边缘聚集的结果。这些发现可能具有临床意义，因为它们至少可以部分解释创伤患者和大手术中使用治疗性低温的好处和弊端。
