AgResearch Ltd., Ruakura Research Centre, Hamilton, New Zealand.
PLoS One. 2020 May 29;15(5):e0233558. doi: 10.1371/journal.pone.0233558. eCollection 2020.
Eye temperature measured using infrared thermography (IRT) can be used as a non-invasive measure of autonomic nervous system (ANS) activity in cattle. The objective of this study was to evaluate if changes in eye temperature (measured using IRT) can be used to non-invasively measure ANS activity in sheep. Twenty, 2 to 4-year-old, Romney ewes were randomly assigned to receive either epinephrine (EPI) or physiological saline (SAL) for 5 min administered via jugular catheter (n = 10 ewes/treatment). Eye temperature (°C) was recorded continuously using IRT for approximately 25 min before and 20 min after the start of infusion. Heart rate and heart rate variability, measured using the root mean square of successive differences (RMSSD) and the standard deviation of all inter-beat intervals (SDNN), were recorded for 5 min before and up to 10 min after the start of infusion. Blood samples were taken before and after the infusion period to measure plasma epinephrine, norepinephrine, cortisol and packed cell volume (PCV) concentrations. During the infusion period, maximum eye temperature was on average higher (P<0.05) in sheep that received epinephrine than those that received saline. On average, heart rate was higher (SAL: 87.5 beats/min, EPI: 123.2 beats/min, SED = 7.07 beats/min; P<0.05), and RMSSD (SAL: 55.3 ms, EPI: 17.3 ms, SED = 14.18 ms) and SDNN (SAL: 54.3 ms, EPI: 21.5 ms, SED = 10.00 ms) lower (P<0.05) in ewes during the 5 min post-infusion period compared with ewes that received saline. An infusion of epinephrine resulted in higher geometric mean epinephrine (P<0.05) and cortisol (P<0.05) but not norepinephrine (P>0.05) concentrations in ewes compared to an infusion of saline. PCV concentrations were higher (P<0.001) by 7 ± 1.0% (mean±SED) in ewes after an epinephrine infusion. These results suggest that heart rate variability is a sensitive, non-invasive method that can be used to measure ANS activity in sheep, whereas change in eye temperature measured using IRT is a less sensitive method.
使用红外热成像（IRT）测量的眼部温度可作为一种非侵入性测量牛自主神经系统（ANS）活动的方法。本研究的目的是评估使用 IRT 测量的眼部温度（通过 IRT 测量）是否可用于非侵入性测量绵羊的 ANS 活动。将 20 只 2 至 4 岁的罗姆尼母羊随机分配接受肾上腺素（EPI）或生理盐水（SAL）静脉内输注 5 分钟（每组 10 只母羊）。在输注开始前和开始后约 25 分钟，使用 IRT 连续记录眼部温度（°C）。在输注开始前和输注开始后 5 分钟内，使用均方根差（RMSSD）和所有心动间隔标准差（SDNN）测量心率和心率变异性。在输注期间和输注后采集血样，以测量血浆肾上腺素、去甲肾上腺素、皮质醇和红细胞压积（PCV）浓度。在输注期间，接受肾上腺素的绵羊的最大眼部温度平均较高（P<0.05），而接受生理盐水的绵羊则较低。平均而言，心率较高（SAL：87.5 次/分钟，EPI：123.2 次/分钟，SED = 7.07 次/分钟；P<0.05），并且 RMSSD（SAL：55.3 ms，EPI：17.3 ms，SED = 14.18 ms）和 SDNN（SAL：54.3 ms，EPI：21.5 ms，SED = 10.00 ms）在输注后 5 分钟内低于接受生理盐水的绵羊（P<0.05）。与生理盐水输注相比，肾上腺素输注导致绵羊的肾上腺素（P<0.05）和皮质醇（P<0.05）的几何均数浓度升高，但去甲肾上腺素（P>0.05）浓度无变化。与生理盐水输注相比，肾上腺素输注后绵羊的红细胞压积（PCV）浓度升高 7 ± 1.0%（均值±SED）。这些结果表明，心率变异性是一种敏感的非侵入性方法，可用于测量绵羊的 ANS 活动，而使用 IRT 测量的眼部温度变化是一种敏感性较低的方法。
