Background: Chronic psychosocial stress impairs memory function and leads to a depression-like phenotype induced by a persistent status of oxidative stress. Hypericum perforatum L. (St. John’s wort) is widely used to relieve symptoms of anxiety and depression; however, its long-term use is associated with adverse effects. Hypericum triquetrifolium Turra is closely related to H. perforatum. Both plants belong to Hypericaceae family and share many biologically active compounds. Previous work by our group showed that methanolic extracts of H. triquetrifolium have potent antioxidant activity as well as high hypericin content, a component that proved to have stress-relieving and antidepressant effects by other studies. Therefore, we hypothesized that H. triquetrifolium would reduce stress-induced cognitive impairment in a rat model of chronic stress.
Objective: To determine whether chronic treatment with H. triquetrifolium protects against stress-associated memory deficits and to investigate a possible mechanism.
Methods: The radial arm water maze (RAWM) was used to test learning and memory in rats exposed to daily stress using the resident–intruder paradigm. Stressed and unstressed rats received chronic H. triquetrifolium or vehicle. We also measured levels of brain-derived neurotrophic factor (BDNF) in the hippocampus, cortex and cerebellum.
Results: Neither chronic stress nor chronic H. triquetrifolium administration affected performance during acquisition. However, memory tests in the RAWM showed that chronic stress impaired different post-encoding memory stages. H. triquetrifolium prevented this impairment. Furthermore, hippocampal BDNF levels were markedly lower in stressed animals than in unstressed animals, and chronic administration of H triquetrifolium chronic administration protected against this reduction. No significant difference was observed in the effects of chronic stress and/or H. triquetrifolium treatment on BDNF levels in the cerebellum and cortex.
Conclusion: H. triquetrifolium extract can oppose stress-associated hippocampus-dependent memory deficits in a mechanism that may involve BDNF in the hippocampus.



中文翻译：

---

金丝桃对慢性心理应激所致大鼠记忆损伤的作用评价：BDNF 的作用


背景：慢性心理社会压力会损害记忆功能，并导致由持续的氧化应激状态引起的抑郁样表型。金丝桃（圣约翰草）广泛用于缓解焦虑和抑郁症状；然而，长期使用它会产生不良反应。 Hypericum triquetrifolium Turra 与H. perforatum密切相关。这两种植物都属于金丝桃科，具有许多相同的生物活性化合物。我们课题组之前的研究表明，三叶草的甲醇提取物具有强大的抗氧化活性，并且金丝桃素含量较高，该成分已被其他研究证明具有缓解压力和抗抑郁的作用。因此，我们假设H. triquetrifolium可以减少慢性应激大鼠模型中应激引起的认知障碍。

目的：确定长期使用三叶草治疗是否可以预防压力相关的记忆缺陷，并研究可能的机制。

方法：使用径向臂水迷宫（RAWM）以居民-入侵者范式测试暴露于日常压力的大鼠的学习和记忆能力。应激和未应激大鼠接受慢性三叶草或媒介物。我们还测量了海马体、皮质和小脑中脑源性神经营养因子（BDNF）的水平。

结果：慢性压力和长期服用三叶草都不影响采集过程中的表现。然而，RAWM 中的记忆测试表明，慢性压力会损害不同的编码后记忆阶段。 H. triquetrifolium阻止了这种损害。此外，应激动物的海马 BDNF 水平明显低于未应激动物，并且长期服用三叶草可以防止这种降低。慢性应激和/或三叶草治疗对小脑和皮质 BDNF 水平的影响没有观察到显着差异。

结论：三叶草提取物可以对抗压力相关的海马依赖性记忆缺陷，其机制可能涉及海马中的 BDNF。