Body surface temperature of rats reveals both magnitude and sex differences in the acute stress response
Body surface temperature of rats reveals both magnitude and sex differences in the acute stress response
复制标题
DOI：
10.1016/j.physbeh.2023.114138
复制
发表时间：
2023-03
影响因子：
2.9
通讯作者：
Chanakarn Wongsaengchan;D. McCafferty;Neil P. Evans;D. McKeegan;R. Nager
中科院分区：
文献类型：
--
作者：
Chanakarn Wongsaengchan;D. McCafferty;Neil P. Evans;D. McKeegan;R. Nager
了解应激的生物学标记与应激源大小的关系是非常必要的，并且可以用于福利评估。体表温度的变化可以用红外热像仪（IRT）来测量，作为对急性应激生理反应的标志。虽然一项鸟类研究表明，体表温度的变化可以反映急性应激的强度，但对于哺乳动物对不同强度应激源的体表温度反应及其性别特异性，以及它们与激素和行为反应的关系，我们知之甚少。在暴露于三种应激源（小笼、圈养或约束锥体）一分钟后，我们使用IRT连续采集成年雄性和雌性褐家鼠（Rattus norvegicus）尾部和眼睛的表面温度，测量时间为30分钟，并与血浆皮质酮（CORT）和行为评估交叉验证热反应。为了获得个体的基线温度和对应激的热反应，大鼠在暴露于应激源前30秒和后30分钟在一个测试场所（它们已经习惯了）成像。在三个压力源的作用下，尾温先是下降，然后恢复到基线温度，甚至超过基线温度。尾温动态在不同应激源之间存在差异；被关在小笼子里的雄性大鼠的体温下降幅度最小，而两性大鼠的体温恢复速度最快。眼睛温度的升高只在应激反应早期区分压力源，而且只在女性中。应激后眼温的升高在雄性的右眼和雌性的左眼更明显。在两性中，围合可能与CORT增长最快有关。这些结果与观察到的行为变化一致，暴露在小笼子中的大鼠运动更大，围起来后更不动。在观察期间，雌性大鼠的尾温和眼温以及CORT浓度没有恢复到应激源前的水平，同时雌性大鼠出现更多的逃跑相关行为。这些结果表明，与雄性大鼠相比，雌性大鼠更容易受到急性约束应激的影响，并强调了在未来的应激源强度研究中使用两性的重要性。该研究表明，IRT测量的急性应激引起的哺乳动物表面温度变化与约束应激的大小有关，表明性别差异，并与激素和行为反应相关。因此，IRT有可能成为一种对无约束哺乳动物进行持续福利评估的非侵入性方法。
Understanding how biological markers of stress relate to stressor magnitude is much needed and can be used in welfare assessment. Changes in body surface temperature can be measured using infrared thermography (IRT) as a marker of a physiological response to acute stress. While an avian study has shown that changes in body surface temperature can reflect the intensity of acute stress, little is known about surface temperature responses to stressors of different magnitudes and its sex-specificity in mammals, and how they correlate with hormonal and behavioural responses. We used IRT to collect continuous surface temperature measurements of tail and eye of adult male and female rats (Rattus norvegicus), for 30 minutes after exposure to one of three stressors (small cage, encircling handling or rodent restraint cone) for one minute, and cross-validated the thermal response with plasma corticosterone (CORT) and behavioural assessment. To obtain individual baseline temperatures and thermal responses to stress, rats were imaged in a test arena (to which they were habituated) for 30 seconds before and 30 minutes after being exposed to the stressor. In response to the three stressors, tail temperature initially decreased and then recovered to, or overshot the baseline temperature. Tail temperature dynamics differed between stressors; being restrained in the small cage was associated with the smallest drop in temperature, in male rats, and the fastest thermal recovery, in both sexes. Increases in eye temperature only distinguished between stressors early in the response and only in females. The post stressor increase in eye temperature was greater in the right eye of males and the left eye of females. In both sexes encircling may have been associated with the fastest increase in CORT. These results were in line with observed behavioural changes, with greater movement in rats exposed to the small cage and higher immobility after encircling. The female tail and eye temperature, as well as the CORT concentrations did not return to pre-stressor levels in the observation period, in conjunction with the greater occurrence of escape-related behaviours in female rats. These results suggest that female rats are more vulnerable to acute restraint stress compared to male rats and emphasise the importance of using both sexes in future investigations of stressor magnitude. This study demonstrates that acute stress induced changes in mammalian surface temperature measured with IRT relate to the magnitude of restraint stress, indicate sex differences and correlate with hormonal and behavioural responses. Thus, IRT has the potential to become a non-invasive method of continuous welfare assessment in unrestrained mammals.