Neuroprotective Effects of Savinin on LPS-Induced Neuroinflammation In Vivo via Regulating MAPK/NF-κB Pathway and NLRP3 Inflammasome Activation

Abstract

The traditional herb Eleutherococcus henryi Oliv. is commonly used to treat inflammatory conditions including rheumatism, arthritis, and hepatitis, as well as mental fatigue and amnesia, according to traditional Chinese medicine (TCM) theory. Savinin is a natural lignan obtained from the roots of E. henryi. The present study was undertaken to determine whether savinin can relieve LPS-induced neuroinflammation and if so, what the mechanism is. Groups of male C57BL/6 mice were administered savinin (5, 10, 20 mg/kg) and DEX (10 mg/kg) by gavage once daily for a continuous 7 days. On the 5th day of continuous pre-administration, LPS (2.5 mg/kg) was injected into the lateral ventricles of the mice for modeling 48 h. We found that treatment with savinin decreased the levels of neuroinflammatory cytokines and histopathological alterations dramatically. Consequently, it improved the LPS-induced neuroinflammatory response in mice. Furthermore, savinin inhibited the up-regulated expression of related proteins in the activated MAPK/NF-κB and NLRP3 inflammasome signaling pathways caused by LPS. Docking studies demonstrated the binding of savinin to three receptors (MAPK, NF-κB and NLRP3) using a well-fitting mode. These findings suggest that savinin may suppress neuroinflammation induced by LPS in vivo via modulating MAPK/NF-κB and NLRP3 signaling pathways.