Shieh Po-Chuen, Tsao Chiung-Wen, Li Jin-Shiou, Wu Hung-Tsung, Wen Ya-Ju, Kou Dai-Huang, Cheng Juei-Tang
Department of Pharmacy, Tajen University, Yen-Pou, Ping Tung Shien 90701, Taiwan, ROC.
Neurosci Lett. 2008 Mar 21;434(1):1-5. doi: 10.1016/j.neulet.2007.12.032. Epub 2007 Dec 23.
Ginsenoside, the active principles in Panax ginseng root, has been demonstrated to show neurotrophic and neuroprotective actions for prevention of neuron degeneration. Deposition of beta-amyloid peptide (Abeta) causes neurotoxicity through the formation of plaques in brains with Alzheimer's disease. Pituitary adenylate cyclase-activating polypeptide (PACAP) is introduced as a neurotrophic factor to promote cell survival. However, effect of Rh2, one of ginsenosides, on PACAP expression induced by Abeta remains unclear. In the present study, we found that Rh2 stimulates PACAP gene expression and cell proliferation in type I rat brain astrocytes (RBA1) cells and both effects were not modified by the estrogen antagonists (MPP or ICI 182780). Also, Rh2 ameliorates the RBA1 growth inhibition of Abeta. Moreover, blockade of PACAP receptor PAC1 using PACAP (6-38) inhibits all the actions of Rh2. These results suggest that Rh2 can induce an increase of PACAP to activate PAC1, but not estrogen receptor, and thereby leads to attenuate Abeta-induced toxicity. Thus, ginseng seems useful in the prevention of dementia.
人参皂苷是人参根中的活性成分，已被证明具有神经营养和神经保护作用，可预防神经元变性。β-淀粉样肽（Aβ）的沉积通过在阿尔茨海默病患者大脑中形成斑块而导致神经毒性。垂体腺苷酸环化酶激活多肽（PACAP）作为一种神经营养因子被引入以促进细胞存活。然而，人参皂苷之一的Rh2对Aβ诱导的PACAP表达的影响仍不清楚。在本研究中，我们发现Rh2刺激I型大鼠脑星形胶质细胞（RBA1）中的PACAP基因表达和细胞增殖，并且这两种作用均未被雌激素拮抗剂（MPP或ICI 182780）改变。此外，Rh2改善了Aβ对RBA1生长的抑制作用。此外，使用PACAP（6-38）阻断PACAP受体PAC1可抑制Rh2的所有作用。这些结果表明，Rh2可诱导PACAP增加以激活PAC1，而非雌激素受体，从而减轻Aβ诱导的毒性。因此，人参似乎对预防痴呆有用。
