Laboratory Animal Resource Center, School of Medicine, Indiana University, Indianapolis, Indiana, USA.
Lab Anim (NY). 2017 Jun 23;46(7):303-307. doi: 10.1038/laban.1298.
When evaluating the effect of husbandry and biomethodologies on the well-being of laboratory mice, it is critical to utilize measurements that allow the distinguishing of acute stress from chronic stress. One of the most common measurements of stress in laboratory animals is the corticosterone assessment. However, while this measurement provides a highly accurate reflection of the animal's response to acute stressors, its interpretation is more prone to error when evaluating the effect of chronic stress. This study evaluated the use of the neutrophil:lymphocyte (NE:LY) ratio as an assessment of chronic stress in male and female C57Bl/6N mice as compared to serum corticosterone. One group of mice was exposed to mild daily stressors for 7 days, while the control group was handled with normal husbandry. The NE:LY ratio and serum corticosterone levels were significantly elevated in the chronically stressed mice, though a significant increase in corticosterone was only significant in males when compared by sex. The chronically stressed mice also demonstrated significantly fewer entries into the open arms and less time spent in the open arms of the elevated plus maze, suggesting that the mild daily stressors had induced a state of distress. The findings of this study confirm that the NE:LY ratio is a valid measurement for chronic stress in the laboratory mouse. However, these assays do not distinguish between distress or eustress, so behavioral and physiological assessments should always be included to determine a complete assessment of the well-being of the mouse.
在评估饲养和生物方法对实验小鼠健康的影响时，使用能够区分急性应激和慢性应激的测量方法至关重要。实验室动物应激的最常见测量之一是皮质酮评估。然而，虽然该测量方法高度准确地反映了动物对急性应激源的反应，但在评估慢性应激的影响时，其解释更容易出错。本研究评估了中性粒细胞与淋巴细胞（NE：LY）比值作为雄性和雌性 C57Bl/6N 小鼠慢性应激评估与血清皮质酮的比较。一组小鼠暴露于轻度日常应激源 7 天，而对照组则进行正常饲养。慢性应激小鼠的 NE：LY 比值和血清皮质酮水平显著升高，尽管与性别相比，雄性小鼠的皮质酮显著升高。慢性应激小鼠在高架十字迷宫的开放臂中的进入次数和时间也明显减少，表明轻度日常应激源已诱导出一种痛苦状态。本研究的结果证实，NE：LY 比值是实验室小鼠慢性应激的有效测量方法。然而，这些检测方法并不能区分痛苦或正性应激，因此应始终包括行为和生理评估，以确定对小鼠健康的全面评估。
