Histomorphometric evaluation of mucin content in stone-containing intrahepatic bile ducts

Although histologic studies of mucin distribution in the peribiliary glands have been conducted, a quantitative study of mucin con tent in intrahepati c bile ducts has vet to be reported, In an attempt to evaluate the mucin co ntent in stone-containing intrahepatic bile ducts, we conducted a study on 25 surgically resected livers with hepatolithiasis. Specimens from 10 liver s without stones served as controls. All specimens were fixed in 10% formal in and sectioned for periodic acid Schiffalcian blue double-stain (PAS-AB; pH 2.5) to evaluate the epithelial mucin content of the intrahepatic bile d ucts. The PAS-AB positive area and the total epithelial area were measured with a computerized image analyzer and the PAS-AB index was calculated as t he proportion of the PAS-AB positive to the total epithelial area, The hist ochemical study showed that epithelial cells in both the intramural glands and extramural glands of stone-containing intrahepatic bile ducts stained h eavily and homogeneously with PAS-AB, while those of controls stained weakl y. The PAS-AB indexes in stone-containing intrahepatic bile ducts were 51.8 +/- 15.88% for mucous cells of intramural glands. 52.86 +/- 9.85% for muco us cells of extramural glands, and 77.29 +/- 21.59% for serous cells of ext ramural glands, These values were all significantly higher than those of co ntrol specimens. However, the PAS-AB index of the epithelial lining in both hepatolithiasis and control specimens were similarly law, indicating the e pithelial lining does not secrete much mucous glycoprotein. The results of this study led us to conclude that stone-containing intrahepatic bile ducts contain art abundant amount of mucous glycoprotein, and mucin is secreted from die peribiliary glands, not from the epithelial lining of the bile duc ts.