Acute carbon tetrachloride feeding induces damage of large but not small cholangiocytes from BDL rat liver

Abstract

Bile duct damage and/or loss is limited to a range of duct sizes in cholangiopathies. We tested the hypothesis that CCl4damages only large ducts. CCl4 or mineral oil was given to bile duct-ligated (BDL) rats, and 1, 2, and 7 days later small and large cholangiocytes were purified and evaluated for apoptosis, proliferation, and secretion. In situ, we measured apoptosis by morphometric and TUNEL analysis and the number of small and large ducts by morphometry. Two days after CCl4 administration, we found an increased number of small ducts and reduced number of large ducts. In vitro apoptosis was observed only in large cholangiocytes, and this was accompanied by loss of proliferation and secretion in large cholangiocytes and loss of choleretic effect of secretin. Small cholangiocytes de novo express the secretin receptor gene and secretin-induced cAMP response. Consistent with damage of large ducts, we detected cytochrome P-4502E1 (which CCl4 converts to its radicals) only in large cholangiocytes. CCl4induces selective apoptosis of large ducts associated with loss of large cholangiocyte proliferation and secretion.

Bile acid feeding increased proliferative activity and apical bile acid transporter expression in both small and large rat cholangiocytes

“…12 In the intrahepatic biliary tree, there are different proliferative compartments that differentially respond to the aforementioned liver injury/toxins. 3,6,8,9,11 Consistent with this novel concept, in rats with BDL only large cholangiocytes undergo replication with enhanced DNA replication and increased number of large bile ducts. 3 Furthermore, a single dose of CCl 4 (administered to rats by gastric gavage) induces ductopenia of large ducts whereas small ducts de novo proliferate to compensate for the loss of proliferative activity of large ducts.…”

“…Two pure (by ␥-GT histochemistry) subpopulations of small and large cholangiocytes were purified from normal rats and rats fed for 1 week 1% TC, 1% TLC, or control diet by counterflow elutriation followed by immunoaffinity separation 3,4,6,7,9,19,20 using a monoclonal antibody against an unidentified antigen expressed by all intrahepatic cholangiocytes. 19 Cell viability (approximately 97%) was determined by trypan blue exclusion.…”

“…Morphometry of frozen liver sections (5 m thick, n ϭ 3 for each group) was performed by point count analysis 7,22 by determining the number of small (Ͻ15 m in diameter 23 ) and large (Ͼ15 m in diameter 23 ) ducts stained for CK-19. 6,7 This technique has been previously used by us 6,7,9,20 to measure intrahepatic ductal mass in both normal and rat livers with ductal hyperplasia. Following staining for CK-19, 6,7 sections were counterstained with hematoxylin and examined in a coded fashion with an Olympus BX 40 microscope (Olympus Optical Co., Ltd., Tokyo, Japan).…”

“…In animal models, cholangiocytes markedly proliferate in response to a number of pathological maneuvers including bile duct ligation (BDL), [2][3][4][5][6] partial hepatectomy, 7,8 or feeding of carbon tetrachloride (CCl 4 ), 6,9 ␣-naphthylisothiocyanate (ANIT), 10,11 or specific bile salts. 12 In the intrahepatic biliary tree, there are different proliferative compartments that differentially respond to the aforementioned liver injury/toxins.…”

“…3 Furthermore, a single dose of CCl 4 (administered to rats by gastric gavage) induces ductopenia of large ducts whereas small ducts de novo proliferate to compensate for the loss of proliferative activity of large ducts. 6,9 In contrast, small and large cholangiocytes participate in the regrowth of the intrahepatic biliary epithelium following partial hepatectomy. 8 Finally, chronic ANIT feeding stimulates proliferative and apoptotic activity of both small and large cholangiocytes.…”