Effect of magnesium sulfate in oxidized lipid bilayers properties by using molecular dynamics

Abstract

Magnesium sulfate (MgSO ₄) has been used as a protector agent for many diseases related to oxidative stress. The effect of MgSO ₄ on the oxidized lipid bilayer has not yet been studied using molecular dynamics calculations. In this work, the effects of oxidation were evaluated by using a POPC membrane model at different concentrations of its aldehyde (-CHO) and hydroperoxide (-OOH) derivatives with and without MgSO ₄. Several quantitative and qualitative properties were evaluated, such as membrane thickness, area per lipid, area compressibility modulus, snapshots after simulation finish, density distributions, time evolutions of oxidized group positions, and radial distributions of oxidized group concerning Mg. Results indicate that in the absence of MgSO ₄ the mobility of oxidized groups, particularly –CHO, toward the surface interface is high. At a low oxidation level of the bilayer there is an increase in the compressibility modulus as compared to the unoxidized bilayer. MgSO ₄, at a low oxidation level, tends to lessen the oxidation effects by lowering the dispersion in the distribution of oxidized species toward the membrane surface and the water region. However, MgSO ₄ does not change the trends of decreasing membrane thickness and area compressibility modulus and increasing area per lipid upon oxidation. In this regard, MgSO ₄ diminishes the electrostatic long-distance attractive interactions between the oxidized groups and the charged headgroups of the interface, owing to the Mg ⁺² and SO ₄ ^-2 screening effects and an electrostatic stabilization of the headgroups, preventing the pore formation, which is well-known to occur in oxidized membranes.

Highlights

• •

  MgSO ₄ in vitro restores oxidized membranes but its molecular mechanism is unclear.

• •

  MD simulations of oxidized lipid bilayers were performed with and without of MgSO ₄.

• •

  A restriction in the mobility of oxidized groups is produced by MgSO ₄.

• •

  Mg ⁺² and SO ₄ ⁼ produce screening effects on the oxidized membranes.

• •

  MgSO ₄ produce a diminution of electrostatic long-distance attractive interactions.