Magnesium sulfate inhibits inflammation through P2X7 receptors in human umbilical vein endothelial cells

Background Magnesium sulfate (MgSO4) is utilized for fetal neuroprotection in preterm birth but its mechanism of action is still poorly understood. P2X7 receptor (P2X7R) is required for secretion of IL-1 beta, and can be blocked by divalent cations such as magnesium (Mg) and its own antagonist, Brilliant Blue G (BBG). We sought to determine whether during inflammation MgSO4 can block endothelial IL-1 beta secretion, using an in-vitro model. Methods Human umbilical vein endothelial cell (HUVEC) cultures were treated with varying doses of LPS, 2 '(3)-omicron-(4-Benzoylbenzoyl) adenosine-5 '-triphosphate (BzATP), BBG and MgSO4 for 3- or 24 h. We determined cell cytotoxicity, apoptosis, IL-1 beta mRNA expression, IL-1 beta production and secretion and P2X7R expression on HUVECs. Results We demonstrated that MgSO4 is efficacious in blocking IL-1 beta-mediated-inflammation in HUVECs, at both the initiation and propagation phases of inflammation. MgSO4 exerts these anti-inflammatory effects via downregulation of P2X7Rs on HUVECs. Conclusion LPS-exposure increases IL-1 beta production and secretion in HUVECs, which is further intensified by P2X7R agonist, BzATP while MgSO4 inhibits IL-1 beta in both presence and absence of BzATP. This effect is similar to the results of P2X7R antagonist, BBG, suggesting that the anti-inflammatory effects of MgSO4 is through P2X7R.