Reversible biliary occlusion in a small animal model: first description of a new technique

BACKGROUND: Experimental models with reversible biliary occlusion resulted in a high mortality of the animals, up to 20–60% according to the literature. Our aim was to assess a safe and valid technique for reversible biliary occlusion with a low mortality. METHODS: We randomized 30 rats into two groups: with bile duct occlusion (BDO, n=18) and with sham manipulation of the extrahepatic bile duct (control, n=12). We used a removable vascular clip for temporary occlusion of the extrahepatic bile duct. The clip was removed on postoperative day (POD) 2. On POD 2, 3, and 5, we measured the hepatocellular injury and metabolic function markers in serum. Activation of mononuclear cells (HIS36) and expression of regeneration markers [cytokeratin 19, hepatic growth factor (HGF)-α, and HGF-β] were determined by immunohistochemistry. RESULTS: The survival rate was 96.67% (1/30); one animal died. The mortality in the BDO group was 6% (1/18) and that in the control group was 0% (0/12). BDO resulted in a sharp increase of hepatocellular injury and cholestatic parameters on POD 2 with a rapid decline till POD 3. Significantly strongest activation of Kupffer cells and expression of proliferation markers were found until POD 5 after BDO. CONCLUSION: The clip technique is a safe, cheap, and valid method for reversible biliary occlusion with an extremely low mortality.