Barrientos Ruth M, Watkins Linda R, Rudy Jerry W, Maier Steven F
Department of Psychology & Center for Neuroscience, University of Colorado, Campus Box 345, Boulder, CO 80309, USA.
Brain Behav Immun. 2009 May;23(4):450-4. doi: 10.1016/j.bbi.2009.01.016. Epub 2009 Feb 6.
To more fully characterize the sickness response in young (3 mo) and older (24 mo) rats, we measured core body temperature (CBT), activity level, and body weight changes for 7 days following a peripheral immune challenge with Escherichia coli. CBT increases were delayed and blunted during the 12h following infection in older rats. Indeed, in aging subjects the initial response was hypothermia, but this was followed by a significant and prolonged elevation in CBT lasting 3 days. Young rats, in contrast, generated a rapid and robust CBT elevation lasting just over a day. Activity level was significantly reduced only on the day of E. coli administration in both young and older rats. Body weight loss was equivalent in both age groups one day after E. coli administration, although there was a trend for older rats to continue losing more weight across the next 6 days than in young rats. This is the first study to examine CBTs in young and older rats for a protracted amount of time, thereby revealing that aging rats do have an exaggerated, albeit delayed, fever which is in keeping with other exaggerated sickness behavioral responses observed in aging rodents.
为了更全面地描述幼龄（3个月）和老龄（24个月）大鼠的疾病反应，我们在用大肠杆菌进行外周免疫攻击后的7天内，测量了核心体温（CBT）、活动水平和体重变化。老龄大鼠在感染后的12小时内，CBT升高出现延迟且幅度减小。实际上，在老年个体中，最初的反应是体温过低，但随后CBT出现显著且持续时间较长的升高，持续3天。相比之下，幼龄大鼠产生了快速且强烈的CBT升高，持续时间略超过一天。在幼龄和老龄大鼠中，活动水平仅在给予大肠杆菌的当天显著降低。给予大肠杆菌一天后，两个年龄组的体重减轻相当，尽管老龄大鼠在接下来的6天里有继续比幼龄大鼠减重更多的趋势。这是第一项在较长时间内检测幼龄和老龄大鼠CBT的研究，从而揭示老龄大鼠确实有过度的、尽管延迟的发热，这与在老龄啮齿动物中观察到的其他过度的疾病行为反应一致。
