An In Vitro Verification of the Effects of Paeoniflorin on Lipopolysaccharide-Exposed Microglia

Abstract

Background. The neuroprotective effects of Paeoniflorin (PF) are well known. Most of the evidence was verified in vivo. We attempted to perform an in vitro verification of the effects of PF in microglia. Methods. A lipopolysaccharide- (LPS-) exposed microglia model was employed. An enzyme-linked immunosorbent assay was used to measure the levels of cytokines in the culture supernatants. A real-time polymerase chain reaction was performed to measure the mRNA expression of cytokines and M1- and M2-like genes. A western blot analysis was used to examine the expression of proteins associated with the nuclear factor-kappa B (NF-κB) signaling pathway. Results. We found that the administration of PF reversed the inflammatory response induced by LPS. It downregulated proinflammatory cytokines and upregulated anti-inflammatory cytokines. This, in turn, alleviated the oxidative injuries, downregulated the expression of M1-like genes, and upregulated the expression of M2-like genes. PF can also reverse the changes in proteins associated with the NF-κB signaling pathway induced by LPS. Conclusions. We provided evidence obtained in vitro concerning the neuroprotective effects of PF via suppressing activation of microglia, which might be associated with the NF-κB signaling pathway. These findings contribute to obtaining a deeper understanding of PF, a potential new treatment for brain injuries.