Oxygen tension-independent protection against hypoxic cell killing in rat liver by low sodium

The role of Na⁺ in hypoxic injury was evaluated by a time-course analysis of damage in isolated livers perfused with N₂-saturated buffer containing standard (143 mM) or low (25 mM) Na⁺ levels. Trypan blue uptake was used to detect non-viable cells. Under hypoxia with standard-Na⁺, trypan blue uptake began at the border between pericentral areas and periportal regions and increased in the latter zone; using a low-Na⁺ buffer, no trypan blue zonation occurred but a homogenous distribution of dye was found associated with sinusoidal endothelial cell (SEC) staining. A decrease in hyaluronic acid (HA) uptake, index of SEC damage, was observed using a low-Na⁺ buffer. A time dependent injury was confirmed by an increase in LDH and TBARS levels with standard-Na⁺ buffer. Using low-Na⁺ buffer, SEC susceptibility appears elevated under hypoxia and hepatocytes was protected, in an oxygen independent manner.