Endoplasmic reticulum stress-mediated apoptosis signal pathway is involved in sepsis-induced liver injury.

Endoplasmic reticulum (ER) stress has been increasingly recognized to have an important role in various liver diseases. Sepsis-induced multi-organ failure remains to have a high mortality rate, and the liver plays a central pathophysiological role. This study aims to explore whether ER stress is involved in liver injury in septic rats. Sepsis was induced via cecal ligation and puncture (CLP). Rats were randomly divided into five groups as follows: sham, CLP 2 h, CLP 6 h, CLP 12 h, and CLP 24 h. They were monitored to record body weight (BW) and liver weight changes for every time point after surgery. The levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were detected via colorimetric activity assays. In addition, the morphological changes of the liver tissue were evaluated by staining the sections with hematoxylin and eosin and observing under light microscopy. The levels of glucose-regulated protein 78 (GRP78), CCAAT/enhancer-binding protein homologous protein (CHOP), and cleaved caspase-12 were detected via Western blot analysis. Apoptosis was detected via terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) method. The results showed that septic rat serums ALT and AST were increased, with the increase being more obvious in the CLP 24 h group. In addition, septic rats appeared to have histopathological abnormalities in the liver. The liver weight and index increased after CLP. No differences were noted in the BW between septic groups. The level of GRP78, CHOP, and cleaved caspase-12 were upregulated after CLP. However, CHOP and caspase-12 were induced later than GRP78. The density of TUNEL-positive apoptotic hepatocytes was significantly increased after 12 h and 24 h CLP. It indicates that the unfolded protein response occurred in the early stage of sepsis-induced liver damage. The ER stress-mediated apoptosis signal pathway is among the mechanisms of septic liver injury and may be a target in clinical prevention and therapy of sepsis-induced liver injury.