Journal of Histochemistry and Cytochemistry, Vol. 50, 1599-1609, December 2002, Copyright © 2002, The Histochemical Society, Inc.
NF
B and Caspase-3 Activity in Apoptotic Hepatocytes of Galactosamine-sensitized Mice Treated with TNF
Dan Tapalagaa,
Gisa Tiegsb, and
Sabine Angermüllera
a Department of Anatomy and Cell Biology II, University of Heidelberg, Heidelberg, Germany
b Institute of Experimental and Clinical Pharmacology and Toxicology, University of Erlangen-Nürnberg, Nürnberg, Germany
Correspondence to:
Sabine Angermüller, Dept. of Anatomy and Cell Biology II, U. of Heidelberg, Im Neuenheimer Feld 307, D-69120 Heidelberg, Germany. E-mail: Sabine.Angermueller@urz.uni-heidelberg.de
Tumor necrosis factor-
(TNF
) induces apoptosis in hepatocytes only under transcriptional arrest induced by galactosamine (GalN). In this study we demonstrated the shuttle of the transcription factor NF
B (nuclear factor-kappa B) in the liver tissue of mice within 30 min4.5 hr hours after GalN/TNF
treatment. NF
B translocation from cytoplasm to the nucleus is initiated by its separation from the inhibitory I
B proteins which include I
B
, I
Bß, and I
B. Thirty minutes after GalN/TNF
administration, NF
Bp65 in hepatocellular nuclei becomes increasingly detectable and reaches its highest level after 2.5 hr. Then export back into cytoplasm begins but, surprisingly, approximately 30% of NF
B remains in the nuclear fraction and appears as an immunoprecipitate in the nuclei of apoptotic hepatocytes. Non-apoptotic hepatocytes do not show any reaction product in the nuclei 4.5 hr after treatment. Correspondingly, the amount of dissociated I
Bß decreases in the cytoplasm up to 2.5 hr and increases again afterwards, although it does not reach the level of the control samples. No evidence of I
Bß in the nuclei was found either immunocytochemically or biochemically. Caspase-3 activity, which is responsible for apoptosis, increases significantly after 3.5 hr. At that time, apoptotic hepatocytes can occasionally be observed and, 4.5 hr after GalN/TNF
treatment, constitute approximately 30% of the hepatocytes.
(J Histochem Cytochem 50:15991609, 2002)
Key Words:
NF
B, I
Bß, caspase-3 activity, apoptosis, hepatocytes, GalN-sensitized TNF
-treated, mice