Effect of acute hypernatremia induced by hypertonic saline administration on endothelial glycocalyx in rabbits

BACKGROUND AND OBJECTIVE: The endothelial glycocalyx (EG) is fragile and sensitive to damage such as exposure to hypernatremia. Our aim was to describe the influence of hypernatremia on the EG in sublingual and brain microcirculation in rabbits. METHODS: Hypernatremia was induced by intravenous administration of 10% NaCl solution. The sublingual and brain microcirculation were evaluated by the Side-stream Dark Field imaging before (T1) and 20 minutes after infusion of 10% saline (T2). Damage to the EG was quantified by automated analysis of Perfused Boundary Region (PBR) indicating the amount of penetration of red blood cells into the EG. Syndecan-1 levels were also measured. RESULTS: Hypernatremia was reached in all 20 animals, the PBR values of the sublingual area raised from 1,98 (0,3) to 2,17 (0,18) μm (p = 0,05). The levels of syndecan-1 (1,23 (0,36); 1,31 (0,33) ng/l, p = 0,3) did not mirror PBR changes. CONCLUSIONS: Hypernatremia increased the PBR within the sublingual microcirculation in our animal model, probably due to compression of the EG related to temporary intravascular hypervolemia and changes of the EG charge in RBC instead of direct damaging effect on EG, which has been excluded by rather unchanged levels of syndecan-1.