Magnesium sulfate provides neuroprotection in lipopolysaccharide-activated primary microglia by inhibiting NF-κB pathway

Background: Magnesium sulfate has been used as an anticonvulsant in severe preeclamptic or eclamptic women prior to surgical trauma, but its effects on neuroinflammation is not well defined. In the present study, we investigated the neuroprotective effects of magnesium sulfate in lipopolysaccharide (LPS)-induced microglia and explored the underlying mechanism. Materials and methods: Microglia was incubated with LPS in the presence or absence of various concentrations of magnesium sulfate, or L-type calcium channel activator BAY-K8644. The levels of inflammatory mediators, such as nitric oxide, prostaglandin E-2, interleukin 1 beta, and tumor necrosis factor alpha, were measured using enzyme-linked immunosorbent assay. The expression of inducible nitric oxide synthase mRNA was detected by reverse-transcription polymerase chain reaction. Nuclear factor kappa B (NF-square kappa B) activity in the nuclear extract of microglia was detected by NF-kappa B p50/p65 transcription factor assay kit. Results: Magnesium sulfate at 5 and 10 mmol/L significantly inhibited the release of nitric oxide, prostaglandin E-2, interleukin 1 beta, and tumor necrosis factor alpha, and the expression of inducible nitric oxide synthase mRNA in LPS-activated microglia. Furthermore, magnesium sulfate inhibited the translocation of NF-kappa B from the cytoplasm to the nucleus in a dose-dependent manner. Notably, these effects were significantly reversed by L-type calcium channel activator BAY-K8644. Conclusions: Magnesium sulfate protects microglia against LPS-induced release of inflammatory mediators, and these effects may be mediated by inhibiting L-type calcium channels and NF-kappa B signaling. Crown Copyright (C) 2013 Published by Elsevier Inc. All rights reserved.