High expressions of caveolins on the proliferating bile ductules in primary biliary cirrhosis

Figure 1 Light microscopic distributions of immunohistochemically stained CAV-1 and -2 in human control liver tissue. A: CAV-1, ×100; B: CAV-2, ×100; C: double staining of CAV-1 and cytokeratin 7, ×100; D: double staining of CAV-2 and cytokeratin 7, ×100; E: CAV-1, ×400; F: CAV-2, ×400; G: double staining of CAV-1 and cytokeratin 7, ×400; H: double staining of CAV-2 and cytokeratin 7, ×400. Hematoxylin counterstain. Immunoperoxidase-positive substances showing the presence of CAV-1 and -2 are observed sparsely on hepatic sinusoidal lining cells and a little immunostaining of CAV-1 and -2 on bile ducts. A: artery, P: portal vein, C: central vein. Arrow denotes bile duct.

Figure 2 Light microscopic distributions of immunohistochemically stained CAV-1 and -2 in PBC stage 1 liver tissue. A: CAV-1, ×100; B: CAV-2, ×100; C: double staining of CAV-1 and cytokeratin 7, ×100; D: double staining of CAV-2 and cytokeratin 7, ×100. Hematoxylin counterstain. Immunostaining of CAV-1 and -2 is observed to some degree on interlobular bile ducts, intense immunostaining on proliferative bile ductules, and some immunostaining on hepatic sinusoidal lining cells. Asterisks denote interlobular bile ducts.

Figure 3 Light microscopic distributions of immunohistochemically stained CAV-1 and -2 in PBC stage 3 liver tissue. A: CAV-1, ×100; B: CAV-2, ×100; C: double staining of CAV-1 and cytokeratin 7, ×100; D: double staining of CAV-2 and cytokeratin 7, ×100. Hematoxylin counterstain. Reaction products showing CAV-1 and -2 are localized abundantly on hepatic sinusoidal lining cells and proliferative bile ductules. Regenerating bile ductules at the interface of portal tracts and necrotic areas are immunostained intensely for CAV-1 and -2, showing significant increase compared to control liver. Arrow denotes proliferative bile ductule.

Figure 4 Western blot analysis of the expression of CAV-1 and -2 proteins in human control and PBC liver tissues. Lane 1: normal liver; lane 2: PBC stage 1 liver; lane 3; PBC stage 3 liver. CAV-1 and -2 are found in abundance in PBC stage 3 specimens, less intensely in PBC stage 1, and is undetectable in normal liver tissue. Samples containing 50 μg of membrane protein were subjected to electrophoresis on SDS/PAGE gel (CAV-1 and -2: 4-20%) and analyzed by blotting.