damage of rat liver tissue caused by repeated and sustained +gz exposure and the mechanism thereof

Abstract

Objective 　To explore the mechanisms of positive acceleration (+Gz) on the damage of rat liver tissue and the effect of +Gz on the expression of JNK/c-Jun in liver cells. Methods 　Twenty four male Wistar rats were randomly divided into 4 groups (n=6): control, +2Gz, +6Gz and +10Gz group. With prone position, the rats in control group were fixed to the turning arm of centrifuge with head towards the axis for 5 minutes. The fixation method in +2Gz, +6Gz and +10Gz group was the same as in the control group. The increase rate of acceleration was 1G/s with a peak-time of 3 minutes, and each +Gz exposure repeated 5 times with an interval of 30 minutes. HE staining was used to observe the morphological changes of liver tissue, fluorescence real-time quantitative PCR to detect the expression of hepatic c-Jun mRNA, and Western blotting to detect the hepatic protein expression of p-c-Jun, c-Jun, p-JNK and JNK. Plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were determined. Results 　The levels of serum ALT and AST increased significantly in +6Gz and, especially, the +10Gz group than in control group and +2Gz group (P<0.05). The same situation also existed in the increase of c-Jun mRNA expression (P<0.05). Hepatic c-jun and p-c-Jun (c-Jun activated form) protein expression increased with the increase of G value. Compared with control group, no change was found in JNK protein expression in the other three groups, but the expression of p-JNK (activated form of JNK) increased in +6Gz and +10Gz groups (P<0.05). HE staining showed the disorganized liver cells with irregular shapes, the unclear cell gap and the vacuolar changes in +6Gz and +10Gz groups. Conclusions 　Repeated and sustained +Gz may cause enhanced expression of c-Jun/ p-c-Jun and p-JNK in hepatic cells. JNK/c-Jun signaling pathway may play an important role in the process of hepatic stress injury. DOI: 10.11855/j.issn.0577-7402.2014.03.15