Effects of seawater immersion at 21 ℃ on major organ functions in rats with hemorrhagic shock

To determine the effects of seawater immersion at 21 ℃ on survival, organ functions, tissue metabolism and homeostasis in rats with hemorrhagic shock.

A total of 128 healthy male SD rats were randomly divided into 4 groups: normal control group (NC), 40% hemorrhagic shock group (HS), normal rats with 21 ℃ seawater immersion (2 h) group (SI), and 40% hemorrhagic shock rats combined with 21 ℃ seawater immersion (2 h) group (HS+SI). The survival rate in each group was observed for 72 h in 2 h after modeling, the changes of cardiac function [cardiac troponin T (cTnT)], liver function [alanine transaminase (ALT) and aspartate aminotransferase (AST) levels], renal function [blood urea nitrogen (BUN) and serum creatinine (SCr) levels], tissue metabolism and internal environment were detected in each group.

As compared with the NC group, the plasma osmolality (OSM), concentrations of Na⁺, K⁺, Cl^- and water contents in the lung and brain were increased, while the Na⁺/K⁺-ATPase activity in the lung and brain was decreased in the HS and SI groups. With the elevation of the damage indexes in heart, liver and kidney functions, the mortality was increased as well in the HS and SI groups. Combination of 21 ℃ seawater immersion resulted in more severe damages induced by simple 40% hemorrhagic shock, shown as further increases in plasma OSM, Na⁺, K⁺ and Cl^- concentrations, and water contents of the lung and brain, as well as further declined Na⁺/K⁺-ATPase activity in the lung (3.81±0.30 U/mg) and brain (7.17±0.51 U/mg) (P<0.05). Serious deterioration was observed in the functions of the heart, liver and kidney, with levels of cTnT, ALT, AST, BUN and SCr elevated to 7.25±0.66 μg/L, 118.60±13.29 U/L, 455.95±46.76 U/L, 19.74±2.12 mmol/L and 56.73±4.08 μmol/L, respectively (P<0.05). The survival rate was reduced to 18.75%, and the median survival time was shortened to 10.50 h in the rats of the HS+SI group.

Seawater immersion at 21℃ exacerbates disorders of the internal environment and tissue metabolism in 40% hemorrhagic shock rats, leading to aggravated multiple organ injury and thus increased mortality.