Hepatocytes in the bile duct-ligated rat express Bcl-2

Am J Physiol. 1997 Jun;272(6 Pt 1):G1587-93. doi: 10.1152/ajpgi.1997.272.6.G1587.

Abstract

Hepatocytes do not express Bcl-2, a repressor of apoptosis. In contrast, cholangiocytes, which are in direct contact with bile, do express Bcl-2. Because cholestasis results in the retention of bile within hepatocytes, we reasoned cholestasis may induce hepatocellular expression of Bcl-2. Thus our aim was to determine whether hepatocytes express Bcl-2 or alter expression of other Bcl-2 family members in cholestasis using the bile duct-ligated (BDL) rat as a model of cholestasis. De novo Bcl-2 expression was observed in hepatocytes of BDL rats assessed by reverse transcriptase-polymerase chain reaction and immunoblot analysis. Immunohistochemistry demonstrated that Bcl-2 expression in hepatocytes was greater in periportal hepatocytes than pericentral hepatocytes. Expression of Bcl-x (an antiapoptotic Bcl-2 family protein) was not altered by bile duct ligation, whereas expression of Bax (a proapoptotic Bcl-2 family protein) increased slightly as determined by Northern and Western blot analyses. Bcl-2-positive hepatocytes isolated from BDL rats were resistant to induction of apoptosis by 50 microM glycochenodeoxycholate. Our results demonstrate, for the first time, expression of Bcl-2 by hepatocytes during cholestasis. We suggest that hepatocellular expression of Bcl-2 during cholestasis is an adaptive phenomenon to resist apoptosis by toxic bile salts.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Apoptosis
  • Bile Ducts / physiology*
  • Cells, Cultured
  • Cholestasis / metabolism
  • Cholestasis / physiopathology*
  • DNA Primers
  • Liver / metabolism*
  • Male
  • Polymerase Chain Reaction
  • Protein Biosynthesis
  • Proto-Oncogene Proteins c-bcl-2 / biosynthesis*
  • RNA, Messenger / biosynthesis
  • Rats
  • Rats, Inbred F344
  • Transcription, Genetic
  • bcl-X Protein

Substances

  • Bcl2l1 protein, rat
  • DNA Primers
  • Proto-Oncogene Proteins c-bcl-2
  • RNA, Messenger
  • bcl-X Protein