Huang-Lian-Jie-Du Decoction alleviates diabetic encephalopathy by regulating inflammation and pyroptosis via suppression of AGEs/RAGE/NF-κB pathways

Ethnopharmacological relevance: Cognitive dysfunction associated with diabetes, known as diabetic encephalopathy (DE), is a grave neurodegenerative condition triggered by diabetes, and persistent inflammation plays a vital role in its development. The renowned traditional Chinese medicine Huang-Lian-Jie-Du Decoction (HLJDD) is clinically proven to manage diabetes mellitus and Alzheimer's disease and is famous for its heat-clearing and detoxifying effects. However, the underlying mechanisms through which HLJDD affects DE remain to be elucidated.

Aim of the study: To explore the beneficial effects of HLJDD on improving cognitive dysfunction in DE mice.

Study design and methods: A diabetic mouse was established through a high-fat diet and subsequent administration of streptozotocin over five consecutive days. After the animals were confirmed to have diabetes, they were treated with HLJDD. After oral administration of HLJDD or metformin for 14 weeks, behavioral tests were used to assess their cognitive capacity. Biochemical analyses were then performed to detect levels of glucose metabolism, followed by histological analyses to assess pathological damage. Furthermore, AGEs/RAGE/NF-κB axis related proteins were detected by Western blot or immunofluorescence techniques. An advanced UPLC-Q-Orbitrap HRMS/MS analytical technique utilizing a chemical derivatization strategy was employed for comprehensive metabolic profiling of carbonyl compounds in the plasma of DE mice.

Results: Pharmacological assessment revealed that HLJDD effectively mitigated cognitive dysfunction, normalized glucose metabolic imbalances, and repaired neuronal damage in DE mice. It reduced neuroinflammation by attenuating carbonyl stress, deactivating astrocytes and microglia, and preserving dopaminergic neurons. Additionally, metabolomics analysis revealed 18 carbonyl compounds with marked disparities between DE and control mice, with 12 metabolites approaching normal levels post-HLJDD intervention. Further investigations showed that HLJDD regulated inflammation and pyroptosis through suppressing AGEs/RAGE/NF-κB pathways.

Conclusion: Our study indicated that HLJDD could ameliorate carbonyl stress via the regulation of carbonyl compound metabolism profiling, and inhibiting the AGEs/RAGE/NF-κB pathway, thereby alleviating inflammation and pyroptosis to exert beneficial effects on DE.