Li Guangjian, Yang Jing, Wang Xu, Zhou Chen, Zheng Xiangyu, Lin Weihong
Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, Jilin 130021, China.
Department of Bioscience, Changchun Normal University, Changchun, Jilin 130031, China.
Food Funct. 2020 Oct 21;11(10):8780-8787. doi: 10.1039/d0fo00524j.
The aim of this study is to examine the antidepressant-like effect of EGCG and get deeper insights into implications of modulating serotonin (5-HT) in the colon and brain. A total of 24 stochastically-selected rats were subdivided into three groups: one group served as the control group, and other two groups were subjected to chronic unpredictable mild stress interventions (CUMS group and CUMS + EGCG group respectively). Before conducting a designed set of behavior tests, all rats were weighed and then forced swimming test (FST) and open field test (OPT) were performed in all rats for the measurement and analysis of central and colonic serotonin levels. In order to determine the extent of CUMS-induced injuries and examine neurological deficits, the method of Nissl staining was implemented accordingly. Meanwhile, haematoxylin-eosin (H&E) staining was employed to detect the structure of the colon. The study found that, due to the involvement of CUMS, the body weight of experimental rats declined, their time of immobility in FST was greater, and the avoidance of central sections in OPT was also greater and more obvious. However, through intervention of the EGCG treatment, either weight loss or depression-related behavior induced by the involvement of CUMS was alleviated in the experimental rats. Comparison of both CUMS and CUMS + EGCG groups indicated that EGCG administration may decrease the level of serotonin (5-HT) in the colon but increase the level of serotonin (5-HT) in the hippocampus. However, it should be noted that the level of 5-HT in peripheral blood did not show any significant difference between both groups. Furthermore, CUMS caused the morphological changes of the hippocampus and structural changes of the colon were noteworthy. Summarily, the investigation results of this experimental study indicated that the intervention of EGCG treatment might have considerable implications in several aspects such as anti-depression, regulation of 5-HT concentration, enhancement of intestinal hyper-permeability, and neuroprotection in the hippocampus.
本研究的目的是考察表没食子儿茶素没食子酸酯（EGCG）的抗抑郁样作用，并更深入地了解调节结肠和大脑中血清素（5-羟色胺，5-HT）的意义。总共24只随机选取的大鼠被分为三组：一组作为对照组，另外两组分别接受慢性不可预测轻度应激干预（分别为CUMS组和CUMS + EGCG组）。在进行一组设计好的行为测试之前，对所有大鼠进行称重，然后对所有大鼠进行强迫游泳试验（FST）和旷场试验（OFT），以测量和分析中枢和结肠血清素水平。为了确定慢性不可预测轻度应激（CUMS）诱导的损伤程度并检查神经功能缺损，相应地采用了尼氏染色法。同时，采用苏木精-伊红（H&E）染色来检测结肠结构。研究发现，由于CUMS的影响，实验大鼠体重下降，在FST中的不动时间更长，在OFT中对中央区域的回避也更明显。然而，通过EGCG治疗的干预，实验大鼠中由CUMS引起的体重减轻或抑郁相关行为均得到缓解。CUMS组和CUMS + EGCG组的比较表明，给予EGCG可能会降低结肠中血清素（5-HT）的水平，但会增加海马体中血清素（5-HT）的水平。然而，应该注意的是，两组外周血中5-HT的水平没有显示出任何显著差异。此外，CUMS导致的海马体形态变化和结肠结构变化值得注意。总之，本实验研究的调查结果表明，EGCG治疗的干预在抗抑郁、调节5-HT浓度、增强肠道通透性以及海马体神经保护等几个方面可能具有重要意义。
