布洛芬对大鼠体温降低作用的昼夜节律研究

目的:研究布洛芬不同时辰给药对大鼠体温降低作用及血药浓度的昼夜节律变化规律。方法:采用随机区组实验设计,60只大鼠分别在不同时间(2:00、6:00、10:00、14:00、18:00、22:00)单次灌胃给予布洛芬颗粒50mg.kg-1,另取10只为空白对照,观察大鼠体温和血药浓度的昼夜节律变化规律,以时间图和余弦法进行分析。结果:大鼠正常体温及用药后体温均呈现明显的昼夜节律变化,峰值相位及振幅无显著改变,仅均值下降;最佳拟合曲线分别为Yti=38.7+0.52Cos(15°×ti—86.80°)和Yti=37.8+0.55Cos(15°×ti—117°)。大鼠在不同时辰给药血药浓度亦呈现明显的昼夜节律变化,明期血药浓度高于暗期,最佳拟合曲线Yti=41.95+5.30Cos(15°×ti—272.83°)。结论:大鼠在不同时辰给予布洛芬,体温和血药浓度均存在昼夜节律的差异。

Effects of Ibuprofen on the Circadian Rhythm Variation of Body Temperature and Plasma Concentration in Rats

OBJECTIVE： To study the effect of different administration time of ibuprofen on the changing characteristics of circadian rhythm about body temperature and plasma concentration in rats. METHODS. 60 rats were given single oral administration of ibuprofen at the dose of 50 mg per kilogram at different time （2 ： 00, 6 ： 00, 10 ： 00, 14 ： 00, 18 ： 00, 22 ： 00） according to a randomized block design with another 10 rats serving as blank control. The effects of ibuprofen on circadian rhythm variations of body temperature and plasma concentration in rats were observed and analyzed using chronogram and cosine method. RESULTS： The body temperature of rats prior to and after administration both showed a significant circadian rhythm, with mean declined only, yet acrophase and amplitude showed no significant differences. The best cosinor curve equation were Yti= 38.7 ＋ 0.52 Cos（ 15° × ti-86.80°） and Y ti = 37.8 ＋ 0.55 Cos（ 15°× ti-117°） respectively. The plasma concentration also showed a significant circadian change in rats at the different time points of administration. The plasma concentration in light phase was higher than that in dark phase, and the best cosinor curve equation was Yti = 41.95＋ 5.30 Cos （15°× ti-272.83°） . CONCLUSION： The differences of circadian rhythm were both shown about body temperature and plasma concentration in rats when ibuprofen was orally administered at the different time points.