Modified Kai-Xin-San ameliorates cognitive impairment in Alzheimer's disease model mice by regulating neuroinflammation and synaptic dysfunction.

Abstract

BACKGROUND: Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by debilitating cognitive decline. Despite its escalating global prevalence, effective disease-modifying therapies remain limited. Modified Kai-Xin-San (MKXS), a derivative of a classic Chinese herbal formula, has shown promise in AD management; however, its precise pharmacological mechanisms require further elucidation. PURPOSE: This study aimed to evaluate the therapeutic effects of MKXS and identify the molecular mechanisms underlying its impact on cognitive function in an AD mouse model. METHODS: The chemical profile of MKXS was characterized using HPLC-Q-TOF-MS, with 24 major constituents quantified via UPLC-PDA. MKXS was administered intragastrically to 5 × FAD mice daily for two consecutive months. Cognitive performance was evaluated using Morris water maze, T-maze, and Y-maze tests. Neuropathological changes, including β-amyloid (Aβ) deposition and neuronal loss, were analyzed via immunostaining, Nissl staining, ELISA, and Western blotting. Synaptic plasticity was assessed through Golgi staining and electrophysiological recordings. Furthermore, network pharmacology and experimental validation were conducted to identify core therapeutic targets with the application of GEO database. RESULTS: Chemical analysis identified 125 constituents in MKXS, with 24 validated against reference standards. In 5 × FAD mice, MKXS treatment significantly ameliorated cognitive impairment, reduced hippocampal Aβ plaque burden, and attenuated neuronal loss. Network pharmacology highlighted neuroinflammation and synaptic regulation as core therapeutic mechanisms. Subsequent validation demonstrated that MKXS suppressed glial overactivation and lowered pro-inflammatory cytokine levels, effectively restoring synaptic plasticity and dendritic spine integrity within the hippocampus. Notably, MKXS significantly upregulated the CaMKIIα/CREB signaling pathway in the hippocampus of 5 × FAD mice. Crucially, pharmacological inhibition of CaMKIIα with KN93 significantly abolished these beneficial effects on synaptic function and memory, confirming the essential role of this signaling axis in MKXS-mediated neuroprotection. CONCLUSION: MKXS alleviated cognitive impairment in 5 × FAD mice by attenuating neuroinflammation and restoring synaptic integrity. These neuroprotective effects were mediated, at least in part, by the activation of the CaMKIIα/CREB signaling pathway. Collectively, these findings underscore the potential of MKXS as a promising multi-target therapeutic intervention for AD.