Received for publication May 25, 2006.
Revised November 12, 2006.
Accepted for publication November 14, 2006.

Analysis of in vivo NF-kappaB Activation during Liver Inflammation in Mice: Prevention by Catalase Delivery

Abstract

Nuclear factor B (NF-B) is a transcription factor that plays crucial roles in inflammation, immunity, cell proliferation and apoptosis. Until now, there have been few studies of NF-B activation in whole animals, because of experimental difficulties. Here, we show that mice receiving a simple injection of plasmid vectors can be used to examine NF-B activation in the liver. Two plasmid vectors, pNF-B-Luc (firefly luciferase gene) and pRL-SV40 (renilla luciferase gene), were injected into the tail vein of mice by the hydrodynamics-based procedure, an established method of gene transfer to mouse liver. Then, the ratio of the firefly and renilla luciferase activities (F/R) was used as an indicator of the NF-B activity in the liver. Injection of thioacetamide or lipopolysaccharide plus D-galactosamine increased the F/R ratio in the liver and this was significantly (P<0.001) inhibited by an intravenous injection of catalase derivatives targeting liver nonparenchymal cells. Imaging the firefly luciferase expression in live mice clearly demonstrated that the catalase derivatives efficiently prevented the NF-B-mediated expression of the firefly luciferase gene. Plasma transaminases and the survival rate of mice supported the findings obtained by the luminescence-based analyses. Thus, this method, which requires no genetic recombination techniques, is highly sensitive to the activation of NF-B, and allows us to continuously examine the activation in live animals. In conclusion, this novel, simple and sensitive method can be used not only for analyzing the NF-B activation in the organ under different inflammatory conditions, but also for screening drug candidates for the prevention of liver inflammation.

Key words: NFkappaB, Regulation of gene expression, Receptor-mediated, Regulation - transcriptional, Oxidative stress