Atypical findings in a rat model for parenteral nutrition–induced cholestasis

The pathophysiology of parenteral nutrition–associated cholestasis (PNAC) in young children is poorly understood. The composition of the total parenteral nutrition (TPN) is reported to be of importance for the occurrence of PNAC. In this study, the effects of parenteral nutrition with different caloric loads and different amounts of lipids were studied in a rat model for PNAC. Four different groups of male Wistar rats were used. In 3 groups, a central catheter was placed in the right jugular vein. The first group (group A) received NaCl 0.9% and had free access to food and water; the other two (groups C and D) received TPN, containing 1142 and 1611 J kg−1 d−1, respectively. In group B, the common bile duct was ligated. Animals were killed after 7 or 14 days; at these points, liver enzymes were measured, and liver histology was assessed. In the bile duct ligation group, all liver enzymes significantly increased compared with baseline. Liver enzymes did not significantly change in the other groups. Histology showed cholestatic changes in the bile duct ligation group. In the parenteral nutrition groups, significant steatotic changes were found, and in the high caloric TPN group, more so than in the TPN group. In this study, TPN was not associated with abnormal liver function tests or with histological evidence of cholestasis. Total parenteral nutrition was associated with steatosis in this rat model, which is a finding commonly reported in the literature. Therefore, it is questionable whether the rat is a good model for TPN-associated cholestasis.