A new method of bile duct cannulation allowing bile collection and re-infusion in the conscious rat

A technique is described for collection of bile from the surgically-prepared, conscious rat after a postoperative recovery period of 7 days. This model can also be used to study enterohepatic recirculation.     

Chronic bile duct cannulation in laboratory rats.

To our knowledge this is the first report of rat bile duct cannulations in which the distal cannula is hemisected but extends to the sphincter of Oddi. It is minimally invasive and requires only about 45 minutes preparation time. In contrast to studies described in the literature, enterohepatic recirculation remains intact but bile can always be separated from pancreatic secretions at investigator discretion in the model. In addition, biliary flow and pressure can be measured without compromise. Acute biliary secretory pressure, under anesthesia, was 17 cm water. Bile flow, averaging 9.6 microliters/min/100 g was measured in unanesthetized rats surviving for 2 weeks (60% of animals monitored). Gross necropsy findings indicated that animals dying in less than 7 days usually suffered bile peritonitis subsequent to catheter rupture of the bile duct or loss from the ligature restraint. Deaths after 2 weeks were usually related to cholestasis due to blockage of the catheter with mineral debris and/or duct tissue. A detailed literature review of bile duct cannulation in rats has been made.     

A technique for creating partial obstruction of the common bile duct in the rat

Partial obstruction of the common bile duct was produced in rats by tightly tying a 0.5 mm stainless steel rod to the proximal common bile duct. The rod was then removed from the ligature leaving a constriction around the duct. Within 2 weeks the bile duct proximal to the partial obstruction was markedly dilated. Liver histology was notable for marked proliferation of the interlobular bile ductules and minimal cholangitis, changes which are characteristic of partial obstruction.     

A novel bile duct cannulation method with tail cuff exteriorization allowing continuous intravenous infusion and enterohepatic recirculation in the unrestrained rat.

A variety of bile duct cannulation methods have been used in the study of biliary excretion in the rat. We now report the validation and use of one such method. In this method, the common bile duct and duodenum were cannulated, the free ends of the cannulae tunnelled through the abdominal wall, passed through a trochar and exteriorized at the ventral aspect of the tail. A purpose-designed stainless steel tail cuff was then attached, to protect the cannulae from the rat. The cannulae were passed through the top of a metabolism cage and attached to a dual swivel that allows the rat freedom of movement within the metabolism cage. Where necessary an additional cannula could be placed in the femoral vein to allow infusion of test material or blood sampling. The results demonstrate that the method is robust and that its use allows a reliable correlation between surgically prepared and intact animals, as physiological parameters are allowed to return to normal prior to inclusion of the animals in the study. The technique allows the animals a great deal of freedom and, as such, is considered to minimize stress associated with the procedure. This fact is reflected in the reliability and reproducibility of the data obtained over the wide range of studies that have been conducted using this method. This method has been in use for over 4 years at Inveresk and this paper describes the authors' experience with the method to date.     

Papillary carcinoma of the common bile duct. Diagnosis by bile drainage cytology

A 54-year-old man with clinical and radiologic findings suggestive of pancreatic carcinoma had cytologic examination of bile drainage fluid specimens prepared by membrane filtration and cytocentrifugation. Examination showed clumps of malignant cells with features most consistent with a well-differentiated papillary neoplasm of bile duct origin, rather than a primary pancreatic carcinoma. Partial pancreatoduodenectomy with resection of the proximal common bile duct confirmed the presence of a small, well-differentiated but invasive papillary bile duct carcinoma. Pancreatic carcinoma and papillary carcinoma of the bile duct are anatomically and biologically different lesions that should be distinguished, when possible, by cytologic examination. In this case, surgical treatment was planned on the assumption that cytologic examination could distinguish a papillary carcinoma of the bile duct from the clinically suspected pancreatic adenocarcinoma.