Differential regulation of c-jun expression in liver and lung of mice after thermal injury.

In addition to skin injury, burns may also damage distant organs. Understanding the mechanisms of distant organ injury will substantially improve the survival of burn patients. Transcription factors are the major regulators of gene expression in response to most types of injury. C-Jun, which is a part of the activator protein-1 transcription factor complex, is one of the major immediate-early response genes, which is rapidly induced after injury. The expression of c-Jun in mouse liver and lung at different time points (3 h to 29 days) after thermal injury was examined by using Reverse Transcription-Polymerase Chain Reaction (RT-PCR), Western blot, and immunohistochemistry. Rapid induction of c-Jun mRNA and protein was observed in the liver 3 h after an 18% TBSA burn. C-Jun expression returned to basal levels within 3 days after injury. In contrast to the up-regulation observed in liver, lungs from the same mice expressed c-Jun constitutively throughout the same time points. The finding that thermal injury leads to up-regulation of c-Jun in liver but not lungs suggests that either the liver has a lower threshold for early response to injury or that different cellular events exist when each organ is stressed.