Xijiaqi Formula attenuates cognitive dysfunction by inhibiting neuroinflammation and promoting neuroplasticity in...

Chronic heart failure (CHF) impairs cognitive function. Xijiaqi Formula (XJQ), a traditional Chinese medicine (TCM) used clinically to treat CHF, demonstrates potential for improving cognition in CHF patients. However, its precise mechanism in treating post-CHF cognitive dysfunction remains unclear. This study systematically investigates XJQ's effects on post-CHF cognitive dysfunction and the underlying mechanisms. The components of XJQ were identified through liquid chromatography-mass spectrometry. CHF was induced in rats via ligation of the left anterior descending coronary artery, followed by six weeks of XJQ treatment. Cardiac function was evaluated through echocardiography and hemodynamic parameters, while cognitive function was assessed using Morris water maze (MWM) and open field tests (OFT). XJQ treatment enhanced both cardiac and cognitive functions in CHF rats. Network pharmacology identified 12 core active components of XJQ and indicated its effect on cognitive dysfunction involved regulating synapses, inflammation, and phosphodiesterase 4 (PDE4)-dependent cyclic adenosine monophosphate (cAMP) signaling. XJQ inhibited microglial and astrocyte activation, decreased proinflammatory cytokines, and mitigated neuronal damage. Notably, XJQ promoted synaptic repair and dendritic growth by downregulating PDE4 and upregulating cAMP, protein kinase A (PKA), cAMP-response element binding protein (CREB), brain-derived neurotrophic factor (BDNF), PSD95, and synapsin I levels. Molecular docking and Bio-layer interferometry assays confirmed direct binding of quercetin, kaempferol, isorhamnetin, and darutoside to PDE4. In conclusion, XJQ alleviates neuroinflammation and enhances synaptic plasticity to improve cognitive dysfunction in CHF rats via the PDE4/cAMP/PKA/CREB signaling pathway. These findings provide valuable insight into the heart-brain axis.