Cattle Encephalon Glycoside and Ignotin Protects Neurons Against Microglia-Induced Neuroinflammation via Elevating BDNF Expression and Inhibiting TLR4/NF-κB Pathway.

Neuroinflammation is involved in the pathology and progression of Alzheimer's disease (AD) and is closely related to microglial activation. We have previously reported that cattle encephalon glycoside and ignotin (CEGI) could inhibit the activation of microglia in APP/PS1 mice, a mouse model of familial AD. However, the anti-neuroinflammatory mechanisms of CEGI have not yet been fully elucidated. Here, we aimed to investigate the role of CEGI in microglia-mediated neuroinflammation in AD. APP/PS1 mice were treated with CEGI intraperitoneally for 30 days, and then their cognition was assessed. We showed that CEGI alleviated cognitive damage with higher nesting scores, preferential indices, and spontaneous alternation rates in APP/PS1 mice. Moreover, CEGI treatment effectively reduced microglial activation and Iba-1 levels in the cortex of APP/PS1 mice. Additionally, CEGI decreased pro-inflammatory factors production and neuroinflammation-mediated neuronal damage in vivo and in vitro. Finally, CEGI upregulated BDNF levels and downregulated TLR4 and p-NF-κB p65 levels in vivo and in vitro. Taken together, these findings indicated that CEGI could attenuate cognitive deficits in APP/PS1 mice and suppress microglia-induced neuroinflammation via increasing BDNF expression and inhibiting the TLR4/NF-κB pathway.