Regulation of the NF-κB/NLRP3 signalling pathway by Shenghui Yizhi decoction reduces neuroinflammation in mice with Alzheimer’s disease

Abstract

Background Shenghui Yizhi Decoction (SHYZD) has exhibited the capacity to enhance cognitive function and learning abilities in individuals diagnosed with Alzheimer’s disease (AD) while ameliorating pre-existing neuroinflammation. Nevertheless, the precise mechanism underlying its therapeutic effects on AD remains to be elucidated.Methods Twenty-four male SAMP8 mice were randomly divided into three groups, and eight male SAMR1 mice were used as a blank control, to examine their learning and spatial memory abilities. The expression of amyloid β1-42 (Aβ1-42) was detected by immunohistochemical staining of hippocampal tissue. ELISA was used to detect the interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α) expressions. Real time PCR was used to detect NOD-like receptor thermal protein domain associated protein 3 (NLRP3), cysteine protease-1 (Caspase-1), and IL-1β mRNA expression. Western blot was used to detect nuclear factor kappa-B (NF-κB), inhibitor of NF-κB α (IκBα), IκB kinase α (IKKα), NLRP3, Caspase-1, and IL-1β protein expression.Results In this study, SAMP8 mice, employed as an AD model, displayed markedly diminished abilities in terms of spatial localization, navigation, and spatial exploration when compared to the blank control group. Additionally, there was a substantial upregulation of Aβ1-42 expression in the hippocampus of these mice, along with a significant increase in the levels of inflammation-associated factors, including IL-1β, IL-6, TNF-α, NLRP3, Caspase-1, as well as the NF-κB pathway-related proteins, namely, NF-κB, IκBα, and IKKα. Moreover, after treatment with positive drugs (donepezil hydrochloride) and SHYZD, the learning abilities of the mice exhibited significant improvements. Furthermore, the hallmark AD protein Aβ1-42, inflammatory factors, and NF-κB/NLRP3 signalling pathway proteins were significantly reduced. These findings collectively suggest that SHYZD exerts a therapeutic effect on AD.Conclusion In summary, the specific molecular mechanisms through which SHYZD alleviates AD and the potential role for SHYZD in the NF-κB/NLRP3 signalling pathway are identified in this study.

Keywords

• Alzheimer’s disease
• neuroinflammation
• NF-κB/NLRP3 signalling pathway
• Shenghui Yizhi decoction
• coordinating heart and kidney