Department of Environmental Sciences, Nova Scotia Agricultural College, Truro, Nova Scotia, Canada.
PLoS One. 2012;7(8):e43990. doi: 10.1371/journal.pone.0043990. Epub 2012 Aug 30.
Liuwei Dihuang (LWDH), a classic Chinese medicinal formula, has been used to improve or restore declined functions related to aging and geriatric diseases, such as impaired mobility, vision, hearing, cognition and memory. Here, we report on the effect and possible mechanisms of LWDH mediated protection of β-amyloid (Aβ) induced paralysis in Caenorhabditis elegans using ethanol extract (LWDH-EE) and water extract (LWDH-WE). Chemical profiling and quantitative analysis revealed the presence of different levels of bioactive components in these extracts. LWDH-WE was rich in polar components such as monosaccharide dimers and trimers, whereas LWDH-EE was enriched in terms of phenolic compounds such as gallic acid and paeonol. In vitro studies revealed higher DPPH radical scavenging activity for LWDH-EE as compared to that found for LWDH-WE. Neither LWDH-EE nor LWDH-WE were effective in inhibiting aggregation of Aβ in vitro. By contrast, LWDH-EE effectively delayed Aβ induced paralysis in the transgenic C. elegans (CL4176) model which expresses human Aβ1-42. Western blot revealed no treatment induced reduction in Aβ accumulation in CL4176 although a significant reduction was observed at an early stage with respect to β-amyloid deposition in C. elegans strain CL2006 which constitutively expresses human Aβ1-42. In addition, LWDH-EE reduced in vivo reactive oxygen species (ROS) in C. elegans (CL4176) that correlated with increased survival of LWDH-EE treated N2 worms under juglone-induced oxidative stress. Analysis with GFP reporter strain TJ375 revealed increased expression of hsp16.2::GFP after thermal stress whereas a minute induction was observed for sod3::GFP. Quantitative gene expression analysis revealed that LWDH-EE repressed the expression of amy1 in CL4176 while up-regulating hsp16.2 induced by elevating temperature. Taken together, these results suggest that LWDH extracts, particularly LWDH-EE, alleviated β-amyloid induced toxicity, in part, through up-regulation of heat shock protein, antioxidant activity and reduced ROS in C. elegans.
六味地黄（LWDH）是一种经典的中药方剂，用于改善或恢复与衰老和老年病相关的功能下降，如运动、视力、听力、认知和记忆受损。在这里，我们报告了 LWDH 介导的对 Caenorhabditis elegans 中β-淀粉样蛋白（Aβ）诱导瘫痪的保护作用及其可能的机制，使用了乙醇提取物（LWDH-EE）和水提取物（LWDH-WE）。化学分析和定量分析表明，这些提取物中存在不同水平的生物活性成分。LWDH-WE 富含单糖二聚体和三聚体等极性成分，而 LWDH-EE 则富含没食子酸和丹皮酚等酚类化合物。体外研究表明，LWDH-EE 对 DPPH 自由基的清除活性高于 LWDH-WE。LWDH-EE 和 LWDH-WE 都不能有效抑制 Aβ在体外的聚集。相比之下，LWDH-EE 可有效延缓表达人 Aβ1-42 的转基因 C. elegans（CL4176）模型中 Aβ诱导的瘫痪。Western blot 显示，尽管在 C. elegans 菌株 CL2006 中观察到 Aβ 沉积的早期阶段有明显减少，但 LWDH-EE 治疗并未诱导 Aβ积累减少，CL2006 持续表达人 Aβ1-42。此外，LWDH-EE 降低了 C. elegans（CL4176）体内的活性氧（ROS），与 LWDH-EE 处理的 N2 蠕虫在 juglone 诱导的氧化应激下的存活增加相关。用 GFP 报告株 TJ375 分析表明，热应激后 hsp16.2::GFP 的表达增加，而 sod3::GFP 的诱导则很小。定量基因表达分析显示，LWDH-EE 抑制了 CL4176 中 amy1 的表达，同时通过升高温度上调 hsp16.2 的表达。综上所述，这些结果表明，LWDH 提取物，特别是 LWDH-EE，通过上调热休克蛋白、抗氧化活性和降低 C. elegans 中的 ROS，缓解了β-淀粉样蛋白诱导的毒性。
