Effects of plastic stenting in common bile duct of rats. A quantitative reaction analysis using collagen and elastin morphometry.

PURPOSE: To evaluate the effects of biliary stenting in rats through analysis of collagen and elastin deposition in the bile ducts. METHODS: Twenty male rats underwent midline laparotomy, duodenotomy and transampullary stenting of the common bile duct with a 22Fr plastic stent. Animals were randomized in 4 groups, with 5 components in each: (I) control, (II) biliary stenting for 7 days, (III) biliary stenting for 14 days, and (IV) biliary stenting for 30 days. Sections of the common bile duct were stained using Hematoxylin Eosin; Sirius Red to quantitate the amount of collagen present; and Weigert's Resorcin-fuchsin to quantitate the amount of elastin present. RESULTS: The percentage of area stained for collagen was 13.4; 21.5; 29.5 and 32.8, for groups I to IV, respectively. The percentage of area stained for elastin fibers was 7.0; 5.2; 4.0 and 2.9, for groups I to IV, respectively. Collagen/Elastin ratio was 2.4; 5.1; 11.0 and 14.4 for groups I to IV, respectively. CONCLUSIONS: The biliary stenting leads to collagen and elastin deposition in the bile ducts; and collagen deposition and collagen/elastin ratio are proportional to the period of stenting.