CHANGES OF BILE-DUCT MUCOSA AFTER CHOLEDOCHODUODENOSTOMY IN RATS

This study investigated the changes of bile duct mucosa in rats after choledochoduodenostomy. Wistar rats were divided into three groups: gr oup I (n = 6) was treated with sham operation as control; group II (n = 10) was treated with common bile duct ligation without choledochoduo denostomy, and group III (n = 12) had both common bile duct ligation a nd choledochoduodenostomy creation 4 days after common bile duct ligat ion. From our observations, retrograde induced cholangitis due to ente ric reflux into the common bile duct is the possible cause of chronic inflammation after choledochoduodenostomy. At the end of the study, Ch oledocholithiasis developed in 5 of 12 rats. Severe dysplasia was pres ent in the bile duct mucosa in 6 of 12 rats in group III, but not in g roup I or II. A technique for silver staining of nucleolar organizing regions (AgNOR) was applied. This technique demonstrated differences i n AgNOR counts between normal mucosa and dysplasia. Under AgNOR stain, the number of AgNOR was significantly greater than in the normal or b enign counterparts and gradually increased from the normal bile duct m ucosa group to the severe dysplasia group (group I 2.1 +/- 0.8, group II 3.2 +/- 1.0, group III 5.3 +/- 1.1). All of these observations sugg est that 'sump syndrome' and bile stasis could occur after choledochod uodenostomy in rats and can result in chronic inflammation of the bile duct. It has been well established that calcium bilirubinate is the m ajor type of choledocholithiasis in Orientals. beta-Glucuronidase from bacteria, such as Escherichia coli present in the biliary tree, hydro lyzes bilirubin diglucuronide to bilirubin. Bilirubin combines with ca lcium in the bile flow to form calcium bilirubinate. Bacterial infecti on plays a key role in calcium bilirubinate stone formation. Since cho ledochoduodenostomy did increase reflux cholangitis, and bacterial inf ection would increase mucin overproduction, bile deconjugation and eve ntually new calcium bilirubinate stones would be formed. The dysplasti c changes in the bile duct mucosa could possibly be related to the pro longed exposure to the biochemically altered infected bile. Thus chole dochoduodenostomy might not be the perfect choice in treating calcium bilirubinate choledocholithiasis in Orientals.