Background/Aims: The aim of this study was to investigate whether in the li
ver, as in other tissues, there is evidence that angiotensin II, acting via
the angiotensin II type I receptor (ATI-R), plays a role in fibrogenesis.
Methods: Sprague-Dawley rats were divided into three groups; sham, bile duc
t ligated (BDL) and BDL + AT1-R antagonist, irbesartan. Real time RT-PCR wa
s utilised to assess gene expression of the AT1 receptor, TGF-beta1 and alp
ha1 (I) collagen in the liver. TGF-beta1 and alpha1 (I) collagen mRNA expre
ssion and localisation were also assessed by in situ hybridisation. TGF-bet
a1 activity was assessed by using the TGF-beta inducible gene product beta
ig-h3. Fibrosis was assessed by the Knodell scoring system, tissue hydroxyp
roline content and picro-sirius red staining.
Results: Real time RT-PCR revealed that there was a 6-fold up-regulation in
ATI receptor expression in BDL animals compared with shams. This was assoc
iated with marked increases in TGF-beta1, beta ig-h3 and alpha1 (1) collage
n gene expression which were attenuated by AT1-RA treatment. However, AT1-R
A therapy produced no significant change in liver histology or hydroxyproli
ne content.
Conclusions: These results suggest that in the liver angiotensin II may pla
y an important role in the fibrogenic response to injury. However, whether
treatment with an AT1-RA will be of therapeutic benefit remains to be deter
mined. (C) 2001 European Association for the Study of the Liver. Published
by Elsevier Science B.V. All rights reserved.