Ginsenoside Rg5 improves cognitive dysfunction and beta-amyloid deposition in STZ-induced memory impaired rats via attenuating neuroinflammatory responses

• Published in: International immunopharmacology Vol. 19; no. 2; pp. 317 - 326
• Main Authors: Chu, Shenghui, Gu, Junfei, Feng, Liang, Liu, Jiping, Zhang, Minghua, Jia, Xiaobin, Liu, Min, Yao, Danian
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.04.2014
• Subjects: Acetylcholinesterase - metabolism; Alzheimer Disease - drug therapy; Alzheimer's disease; Amyloid beta-Peptides; Animals; Anti-Inflammatory Agents - pharmacology; Anti-Inflammatory Agents - therapeutic use; Behavior, Animal - drug effects; Choline O-Acetyltransferase - metabolism; Cognition Disorders - chemically induced; Cognition Disorders - drug therapy; Cognition Disorders - metabolism; Disease Models, Animal; Ginsenoside Rg5; Ginsenosides - pharmacology; Ginsenosides - therapeutic use; Inflammation; Interleukin-1beta - metabolism; Male; Maze Learning - drug effects; Memory - drug effects; Neuroprotective Agents - pharmacology; Neuroprotective Agents - therapeutic use; Panax ginseng; Rats; Rats, Wistar; Streptozocin; Tumor Necrosis Factor-alpha - metabolism; β-Amyloid; β-Amyloid; Inflammation; Ginsenoside Rg5; Alzheimer's disease
• ISSN: 1567-5769; 1878-1705
• DOI: 10.1016/j.intimp.2014.01.018

Neuroinflammatory responses play a crucial role in the pathogenesis of Alzheimer's disease (AD). Ginsenoside Rg5 (Rg5), an abundant natural compound in Panax ginseng, has been found to be beneficial in treating AD. In the present study, we demonstrated that Rg5 improved cognitive dysfunction and attenuated neuroinflammatory responses in streptozotocin (STZ)-induced memory impaired rats. Cognitive deficits were ameliorated with Rg5 (5, 10 and 20mg/kg) treatment in a dose-dependent manner together with decreased levels of inflammatory cytokines TNF-α and IL-1β (P<0.05) in brains of STZ rats. Acetylcholinesterase (AChE) activity was also significantly reduced by Rg5 whereas choline acetyltransferase (ChAT) activity was remarkably increased in the cortex and hippocampus of STZ-induced AD rats (P<0.05). In addition, Congo red and immunohistochemistry staining results showed that Rg5 alleviated Aβ deposition but enhanced the expressions of insulin-like growth factors 1 (IGF-1) and brain derived neurophic factor (BDNF) in the hippocampus and cerebral cortex (P<0.05). Western blot analysis also demonstrated that Rg5 increased remarkably BDNF and IGF-1 expressions whereas decreased significantly Aβ deposits (P<0.05). Furthermore, it was observed that the expressions of COX-2 and iNOS were significantly up-regulated in STZ-induced AD rats and down-regulated strongly (P<0.05) by Rg5 compared with control rats. These data demonstrated that STZ-induced learning and memory impairments in rats could be improved by Rg5, which was associated with attenuating neuroinflammatory responses. Our findings suggested that Rg5 could be a beneficial agent for the treatment of AD. •Ginsenoside Rg5 improved cognitive deficits in STZ-induced AD rats.•Rg5 alleviated Aβ deposition and regulated AChE and ChAT activities.•Rg5 enhanced the expressions of IGF-1 and BDNF.•Rg5 attenuated neuroinflammatory responses in STZ-induced AD rats.