Swertiamarin ameliorates cognitive dysfunction by improving hyperglycemia and neuroinflammation in type 2 diabetic rats via activation of the PI3K/AKT/GSK3β signaling pathway.

Abstract

Introduction: Diabetic encephalopathy (DE) is a central nervous complication of type 2 diabetes (T2D). Swertiamarin (SW) is a secoiridoid glycoside reported to have anti-hyperglycemic properties in T2D animal models. Nonetheless, the precise function of SW in T2D-induced DE remains unclarified.

Material and methods: A T2D rat model was established by high-fat diet feeding plus streptozotocin injection, followed by SW administration. Fasting blood glucose and insulin levels were determined. The Morris water maze test was implemented to evaluate rat cognitive function. Hematoxylin-eosin staining was performed for hippocampal morphological observation. Hippocampal p-tau level was detected using immunofluorescence staining. ELISA was utilized to determine inflammatory cytokine production. Western blotting was performed to estimate PI3K/Akt/GSK3 β signaling-related protein levels.

Results: Swertiamarin treatment improved spatial learning and memory and reduced fasting blood glucose as well as insulin levels in T2D rats. SW ameliorated hippocampal morphological changes, reduced tau phosphorylation, and attenuated the inflammatory response in T2D rat hippocampal tissues. SW restored PI3K/Akt/GSK3 β signaling in diabetic rat hippocampus.

Conclusions: Swertiamarin exerts anti-diabetic and anti-inflammatory effects possibly by activating PI3K/Akt/GSK3 β signaling, thereby ameliorating cognitive impairment in T2D rats.