Healing Process of the Guinea Pig Common Bile Duct after End-to-End Anastomosis: Pathological Evaluation after 6 Months

Abstract

Background: The healing process of an injured bile duct is always associated with stricture formation, the specific mechanism of which remains unclear. Our objective in this study was to establish a guinea pig common bile duct end-to-end anastomosis (EEA) model after total transection of the common bile duct and to assess the postoperative healing process after 6 months. Materials and Methods: Thirty-two male guinea pigs were randomly divided into 4 groups with or without operation (a control group without operation and 3 groups examined 2, 3 and 6 months after biliary EEA reconstruction, respectively). Histological, immunohistochemical (proliferating cell nuclear antigen, α-smooth muscle actin, h-caldesmon, and Bcl-2 expression) and ultrastructural characteristics were examined and evaluated. Results: Myofibroblasts (MFBs) were differentiated from smooth muscle cells by α-SMA and h-caldesmon staining. Gross inspection of operated bile ducts revealed coarctation formation at the anastomotic stoma. Histological and immunohistochemical examinations showed significant inflammatory reaction, the presence of MFBs, epithelial proliferation and glandular element hyperplasia. Bcl-2 expression decreased in groups 2 and 3, indicating an epithelial self-protecting mechanism. Conclusions: A guinea pig common bile duct EEA model was successfully established. Glandular elements, bile duct epithelial cells and MFBs all played crucial roles in the bile duct healing process. It seems important to elucidate the pathomechanisms of these components for restoring bile duct physiological function.

Mechanism of scar formation following Roux-en-Y choledochojejunostomy in a novel rat model of obstructive jaundice

“…Myofibroblasts are cells with characteristics of both fibroblasts and smooth muscle cells, mainly transformed from fibroblasts due to local stimulation. Zhang et al found that, in the early stage of the healing process, α-SMA-positive cells appeared in all layers of the bile duct wall after end-to-end anastomosis of the common bile duct in guinea pigs, mainly concentrated in the muscular and intimal layers, and myofibroblasts proliferated obviously at the same time; however, at 6 months after the operation, the number of α-SMApositive cells decreased (31). We also found that in the early stage after CJS, α-SMA cells were highly expressed, which reflected that the anastomotic stoma was stimulated by inflammation; fibroblasts proliferated actively and gradually transformed into myofibroblasts.…”

Therapeutic Effect of Combining Anisodamine With Neostigmine on Local Scar Formation Following Roux-en-Y Choledochojejunostomy in a Novel Rat Model

“…It is the recurring inflammatory after the RCJS procedure at anastomotic stoma secondary to intestinal fluid reflux that causes local scar formation and leads to aggravation of anastomotic stenosis after surgery as time goes by, showing proliferation of fibroblasts and myofibroblasts in the bile duct wall as their main performance pathologically ( Zhang et al, 2011 ). Siqueira et al ( 2017 ) asserted that, after receiving end-to-end anastomosis, the proportion of collagen and TGF-β1 in the pig’s common bile duct wall in the operation group was significantly higher than that in the sham operation group while showing active proliferation of fibroblasts in the operation group.…”

Interest of a new biodegradable stent coated with paclitaxel on anastomotic wound healing after biliary reconstruction

“…A large number of myofibroblasts in biliary scars proliferate actively and secrete excessive collagen fibers during the healing process of anastomotic stoma, resulting in scar contraction, followed by benign bile duct stricture [1][2][3][4]. A large number of myofibroblasts in biliary scars proliferate actively and secrete excessive collagen fibers during the healing process of anastomotic stoma, resulting in scar contraction, followed by benign bile duct stricture [1][2][3][4].…”