绿茶多酚对心理应激大鼠行为表现的影响

Effect of green tea polyphenols on behavioral performances in psychological stress rats

目的观察绿茶多酚对心理应激大鼠行为、认知行为以及学习和记忆能力的影响。方法将Wistar大鼠随机分为5组:正常对照组(CT)、应激对照组(SCT)和低、中、高剂量GTPs干预应激组(SLG、SMG和SHG)。采用束缚应激3周建立心理应激动物模型。通过旷场实验了解动物的自主探究行为改变,以水迷宫实验检验动物的认知行为,以避暗实验检测动物的学习和记忆能力。分别以放免法、化学荧光法、双抗夹心ELISA法检测血浆皮质醇水平、去甲肾上腺素和多巴胺含量以及IL-6和IL-2水平。结果各应激组动物的血浆皮质醇水平明显升高,SMG组和SHG组血浆皮质醇与CT组相比显著升高,但较SCT组明显降低。与CT组相比,SCT组动物在旷场中的潜伏期延长,其穿格数、直立次数减少;SLG组动物的表现与SCT组相近,而SMG组和SHG组动物只出现穿格数的减少,而且,SMG组和SHG组动物的潜伏期和直立次数与SCT组比较也存在显著性差异。避暗反应结果显示,各应激组动物的潜伏期均明显延长,而电击次数仅在SCT组和SLG组动物出现显著增加。水迷宫测试显示,与CT组比较,SCT组和SLG组动物完成水迷宫所需的时间和发生错误的次数均明显增加。另外,与SCT组相比,SMG组和SHG组动物完成水迷宫所需的时间和错误次数以及避暗反应电击次数均明显降低。各应激组动物在束缚应激后,其血浆IL-6和IL-2水平均明显升高;SCT组和SLG组动物血浆NE和DA水平显著降低,而SMG组和SHG组动物未见显著性变化。与SCT组相比,SMG组和SHG组动物血浆NE和DA水平明显升高,且血浆IL-6含量亦显著增加。结论心理应激引起动物应激激素分泌增加,行为学表现异常,而适量补充GTPs可改善心理应激机体的行为学表现,提高应激机体的自主活动和探究行为、认知功能以及学习、记忆能力。

Objective This study was conducted to explore the effects of green tea polyphenols modulation on changes of behavioral performances in psychological stress rats. Methods The animal model of psychological stress was developed by restraint stress for 3 weeks. Wistar rats were randomly assigned to five groups as follows： control group （CT）, stress control group （SCT）, and three stress groups with low, medium and high-doses of green tea polyphenols modulation respectively （SLG, SMG and SHG）. The changes of behavioral performances were examined by open-field test, water maze and step-through test. Serum levels of cortisol, catecholamines, interleukin-6 and interleukin-2 were also detected. Results The levels of serum cortisol were all increased obviously in the four stress groups. Furthermore, serum cortisol levels in SMG and SHG were decreased than that of SCT. The behavioral performances of SCT rats in open-field test, stepthrough test and water maze were all changed evidently in contrast to that of CT rats. On the one hand, the changes of behavioral performances in SLG rats were similar to SCT rats. On the other hand, these changes were improved in SMG and SHG rats. In addition, compared with CT group, the levels of plasma IL-6 and IL-1 were increased clearly in the four stress groups, and the contents of serum norepinephrine and dopamine in SCT and SLG groups were decreased dramatically. The serum norepinephrine and dopamine levels in SMG and SHG rats were increased in contrast to that of SCT rats. Conclusion Our results suggested that psychological stress can impair body＇s behavioral performances, and moderate green tea polyphenols modulation may improve these abnormal changes.