[Protective effect and mechanism of mild hypothermia on liver injury after cardiopulmonary resuscitation in pigs].

To investigate the effect of mild hypothermia therapy on liver after cardiopulmonary resuscitation. Thirty-three inbred Chinese Wuzhishan (WZS) minipigs, weighted (28±2) kg, were used to establish a ventricular fibrillation model. And 30 animals survived after cardiopulmonary resuscitation reached basic life support. The surviving animals were randomly divided into two groups: mild hypothermia group (group M, 15) and conventional treatment group (group C, 15). All the animals were observed for 24 hours. Blood samples were extracted at baseline, 0.5, 1, 2, 4, 6, 12 and 24 h after successful resuscitation. The concentrations of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were detected at the time points. The enzyme-linked immunosorbent assay (ELISA) was used to detect the concentrations of interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-α). The data were compared between the two groups, LSD test was used when the variance was homogeneous, and Tamhane T2 test was used when the variance was uneven. Eleven pigs (73.3%) in the group M and 8(53.3%) in the group C survived at 24 h after successful resuscitation, with no statistically significant difference between the two groups (χ(2)=1.229, 0.225). After successful resuscitation, the AST, ALT increased in both group but less in M group (all 0.05). After successful resuscitation, the concentrations of TFN-α and IL-6 in the blood increased in both groups, reached the peak at 4h, and then decreased gradually. The concentrations of TFN-α in group M were lower than those in group C at 0.5, 2, 4 and 6 h after successful resuscitation (0.01, 0.01, 0.87, 0.86, all 0.05). The concentrations of IL-6 in the group M were lower than those in group C at 0.5, 1, 2 and 4 h after successful resuscitation (0.23, 0.78, 0.11, 0.80, all 0.05). After successful resuscitation, the release of inflammatory mediators, such as TNF-α and IL-6, and cell apoptosis may involve in liver ischemia reperfusion injury. After successful resuscitation, the liver undergoes ischemia-reperfusion injury, which may be related to the release of inflammatory mediators such as TNF-α and IL-6. Mild hypothermia therapy can prevent the release of TNF-α, IL-6 to reduce the degree of liver damage after resuscitation.