Mphahlele Noko R, Fuller Andrea, Roth Joachim, Kamerman Peter R
School of Physiology, Univ. of the Witwatersrand, 7 York Road, Parktown 2193, South Africa.
Am J Physiol Regul Integr Comp Physiol. 2004 Oct;287(4):R863-9. doi: 10.1152/ajpregu.00064.2004. Epub 2004 Jun 24.
Most experimentally induced fevers are acute, usually lasting approximately 6-12 h, and thus do not mimic chronic natural fevers, which can extend over several days or more. To produce a model of chronic natural fever, we infused eight goats (Capra hircus) intravenously with 2 ml of 2 x 10(11) cell walls of Staphylococcus aureus (S. aureus) for 6 days using osmotic infusion pumps (10 microl/h) while measuring changes in body temperature, behavior, and plasma cortisol concentration. Seven control animals were infused with sterile saline. Abdominal temperature-sensitive data loggers and osmotic infusion pumps were implanted under halothane anesthesia. To compare our new model with existing models of experimental fever, we also administered 2-ml bolus intravenous injections of 2 x 10(11) S. aureus cell walls, 0.1 microg/kg lipopolysaccharide (Escherichia coli, serotype 0111:B4), and sterile saline in random order to six other goats. Bolus injection of lipopolysaccharide and S. aureus induced typical acute phase responses, characterized by fevers lasting approximately 6 h, sickness behavior, and increased plasma cortisol concentration. Infusion of S. aureus evoked prolonged fevers, which lasted for approximately 3 days, starting on day 4 of infusion (ANOVA, P < 0.05), and did not disrupt the normal circadian rhythm of body temperature. However, pyrogen infusion did not cause plasma cortisol concentration to rise (ANOVA, P > 0.05) or the expression of sickness behavior. In conclusion, infusion of S. aureus produced a fever response resembling that of sustained natural fevers but did not elicit the cortisol and behavioral responses that often are described clinically and during short-term experimental fevers.
大多数实验性诱导的发热是急性的，通常持续约6 - 12小时，因此无法模拟可延续数天或更长时间的慢性自然发热。为了建立慢性自然发热模型，我们使用渗透式输液泵（10微升/小时），给8只山羊（Capra hircus）静脉输注2毫升含有2×10¹¹个金黄色葡萄球菌（S. aureus）细胞壁的溶液，持续6天，同时测量体温、行为和血浆皮质醇浓度的变化。7只对照动物输注无菌生理盐水。在氟烷麻醉下植入腹部温度敏感数据记录器和渗透式输液泵。为了将我们的新模型与现有的实验性发热模型进行比较，我们还对另外6只山羊随机进行了2毫升的静脉推注，分别注射2×10¹¹个金黄色葡萄球菌细胞壁、0.1微克/千克脂多糖（大肠杆菌，血清型0111:B4）和无菌生理盐水。推注脂多糖和金黄色葡萄球菌诱导了典型的急性期反应，其特征为发热持续约6小时、出现患病行为以及血浆皮质醇浓度升高。输注金黄色葡萄球菌引发了持续发热，从输注第4天开始，持续约3天（方差分析，P < 0.05），且未扰乱正常的体温昼夜节律。然而，热原输注并未导致血浆皮质醇浓度升高（方差分析，P > 0.05）或出现患病行为的表现。总之，输注金黄色葡萄球菌产生的发热反应类似于持续性自然发热，但未引发临床及短期实验性发热中常见的皮质醇和行为反应。
