Imaging analysis of luciferase expression in I κB α-luc transgenic mice treated with LPS. A. I κB α-luc transgenic mice were imaged at T = 0, 2, 4, 7 and 24 hours after treatment with LPS (1 mg/kg, i.p., n = 4 for males, n = 6 for females). Representative mice from each treatment group are shown. The color overlay on the image represents the photons/second emitted from the mouse body in accord with the pseudo-color scale shown on the right of the images. Red represents the highest photons/sec while blue represents the lowest photons/sec. B. Quantification of the luciferase signal from the abdominal region of the body. Data are means luciferase activity (billion photon/second) ± SE. Statistical analysis was done for male and female combined data. * indicates a significant induction of luciferase signal by LPS (P = 0.002). C. Northern blot analysis of IκBα mRNA in the liver tissue. Liver tissue was harvested from saline (control) or LPS treated I κB α-luc female mice at 4 hours after treatment and processed for RNA isolation. A total of 2 μg of RNA was analyzed by Northern blot. Equal loading was demonstrated by 28S rRNA.