Comparison of liver injury during resuscitation with different crystalloid solutions in a rat model of hemorrhagic shock

Objective To compare the degree of liver injury during resuscitation with different crystalloid solutions in a rat model of hemorrhagic shock. Methods Forty-eight SPF healthy male Sprague-Dawley rats, aged 7-9 weeks, weighing 280-320 g, were assigned into 4 groups (n=12 each) using a random number table: sham operation group (group S), normal saline group (group NS), Ringer′s lactate solution group (group RL) and Ringer′s malate solution group (group RM). Hemorrhagic shock was induced by withdrawing blood from the right internal jugular vein until mean arterial pressure was reduced to 35-45 mmHg which was maintained for 1 h. The internal jugular vein and artery were cannulated after anesthetization, but no animals were subjected to hemorrhage in group S. The crystalloid solution (2 times the volume of blood loss) was infused intravenously over 30 min starting from 1 h of shock.The animals were resuscitated with 0.9% sodium chloride solution in group NS, with Ringer′s lactate solution in group RL, and with Ringer′s malate solution in group RM. Mean arterial pressure was continuously monitored and recorded during the experiment.Before shock (T1), at 1 h of shock (T2) and at 4 h after resuscitation (T3), blood samples were collected from the right internal jugular vein for determination of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) concentrations by enzyme-linked immunosorbent assay.Rats were sacrificed at T3, and livers were removed for measurement of malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in liver tissues (using colorimetric method) and for examination of pathological changes of liver tissues (with light microscope). Results Compared with group S, the serum ALT and AST concentrations at T2, 3 and SOD activity and MDA content at T3 were significantly increased in NS, RL and RM groups (P<0.05). Compared with group NS or group RL, the serum ALT and AST concentrations were significantly decreased, the SOD activity was increased, and the MDA content was decreased at T3 (P<0.05), and the pathological changes of liver tissues were significantly attenuated in group RM. Conclusion Ringer′s malate solution produces better efficacy than normal saline and Ringer′s lactate solution when used for resuscitation and mitigating liver injury in a rat model of hemorrhagic shock. Key words: Malate; Fluid resuscitation; Hemorrhagic shock; Liver