Establishment Of Mice Liver Injury Model And Its Application To Restraint Stress

Liver disease is one of the major diseases threatening the health of people in China because of its high morbidity and mortality. Liver injury animal model is very important in the study of pathogenesis of liver disease and drug development. There are many types of liver diseases, but most of them can cause liver inflammation and eventually lead to varying degrees of hepatic injury. Carbon tetrachloride is the common chemical for production of hepatic injury animal model, the carbon tetrachloride induced acute and chronic liver injury models were widely used in the study of liver diseases because of its high success rate and good repeatability of modeling. However, carbon tetrachloride is high toxic for human, therefore, to explore less toxic and high safety of chemicals for producation of liver injury animal model is very urgent. Previous studies showed that D-galactosamine liver injury model in rat also has a high success rate and good repeatability of modeling, and importantly, D-galactosamine is far less toxic for human than carbon tetrachloride. However, the D-galactosamine-induced liver injury model in mouse has not been reported yet. In this study, we established the acute and chronic liver injury mouse models using D-galactosamine and carbon tetrachloride. We observed the hepatic tissue change, cell morphology and fibrosis using hematoxylin-eosin staining (HE) and masson staining assays, and measured the levels of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) using the conventional biochemical methods. We evaluated the liver injury mouse models through the analysis of liver pathological morphology and serum biochemical indices. The results show that D-galactosamine induced liver injury in mouse model was successfully established by intraperitoneal injection. The model could be a new choice for the study of liver diseases and drug development.Stress is a nonspecific adaptive response when the body was stimulated.It is a physiological and psychological state of confrontation with the environment in order to maintain homeostasis. Restraint stress,as a non-invasive stimulation,can well simulate human states such as "out of control" crowded, frustration and other daily challenging conditions, especially it can mimic working state in the space shuttle. However, it is still not clear whether restraint stress during acute or chronic liver injury can improve the resistant ability of body and reduce the degree of liver injury. We employed the restraint stress quantitatively on theacute and chronic liver injury mouse models regularly, observed the hepatic lobules, cell morphology and fibrosis using the HE and masson stained liver tissue slides, and measured the levels of serum AST and ALT using the conventional biochemical methods, and then analyzed the effects of restraint stress on liver injury. The results show that restraint stress reduced liver cell damage and liver fibrosis, and significantly decreased the serum AST and ALT levels. These results suggest that restraint stress has a protective effect on liver injury. In addition, we measured the levels of P450enzymes,super oxide dismutase(SOD) and lipid peroxidation end product malondialdehyde(MDA) in liver homogenates using the enzyme-linked immunosorbent assay(ELISA).We found that the levels of P450enzymes and MDA significantly decreased after restraint stress.On the contrary, the SOD levels were significantly increased.These results suggest restraint stress might reduce the levels of oxidation products, thereby inhibiting the oxidative stress-induced damage to the liver cells. These results will be of great help to explore the mechanism under lying protective mechanism of restraint stress on liver injury via oxidative stress pathway and will be also helpful to the development of new drugs for the treatment of non-invisive liver injury and provide reference data for Space medicine.