The Establishment Of Leporine Model Of Traumatic Biliary Stricture And Development Of Mitomycin C Eluting Stent

ObjectiveThe purpose is to explore the establishment of animal model of traumatic bile duct stenosis and study the pathological basis of stricture of bile duct injury. Produce a kind of biliary stent with, Mitomycin C-eluting and observe the law of drug delivery from the stent.MethodsPart I:10New Zealand rabbits (3±0.2kg) were randomly divided into experimental group1(n=5) and experimental group2(n=5) to be making bile duct stenosis model respectively. The experimental group1underwent bile duct part suturing method; experimental group2rowed bile duct contact with electrocoagulation. General conditions, survival of the animals and Changes in liver function were observed after surgery; observe the histological changes of bile duct after30days; immunohistochemistry SP method was used to measure transforming growth factor-β1(TGF-β1) anda-Smooth muscle actin(a-SMA) expression.Part Ⅱ:The powder both the Mitomycin C (MMC) and poly lactic acid (PLA) dissolved in the common solvent tetrahydrofuran (THF) with a drug concentration of1%.6F biliary soaked in the above solvents. After10minutes, remove the vacuum drying, and stored at room temperature. Calculate the quality of the stent contained in MMC by measuring changes in the quality. PBS buffer (PH7.4) diluted Mitomycin C for the standard solution and analyzed the ultraviolet peak area at365nm. Mitomycin C-eluting stents soaked in PBS, placed in shaker with a constant temperature of37℃continuing soaked24h, and then soaked in fresh PBS solution, every day repeated to soak up until30days. Standard PBS solutions as the control group, the chromatographic analysis of specimens from the leaching solution for1-30days, calculated the concentration of MMC in the leaching solution. ResultsPart Ⅰ:The two methods are able to lead to bile duct stricture. Survival rate was no significant difference in the two experimental groups after30days; two groups of animals before surgery and postoperative liver function test results was statistically significant (P<0.05); Stricture formation of the experimental animals; On the segment of the bile duct was significantly expanded to about7-8mm, the gallbladder can be seen significantly increased. Inflammatory cell infiltration, collagen fibers in the submucosal were observed by pathology. The immunohistochemistry results showed that the stenosis bile duct of TGF-β1and a-SMA expression were higher than normal bile duct.Part Ⅱ:The quality of Mitomycin C contained in the stent was detected. MMC on the stent of capacity was up to216.2±2.04μg; per unit area contained in the drug amount was0.732±0.007μg/mm2. Mitomycin C can be sustained release from the stent surface. The first day the mean concentration was1.81±0.06μg/ml; the second was1.24μ0.04μg/ml; then fluctuated in0.61-0.84μg/ml; after21th days the mean concentration had slightly lower and the mean concentration of0.51±0.01μg/ml at30th days.ConclusionPart I:Part suturing method and the electrocoagulation can produce the animal model of traumatic bile duct stricture. Collagen fibrous tissue was hyperplasia in the bile duct stenosis region. The high expression of TGF-β1and a-SMA suggested that fibroblasts play an important role in the bile duct stricture formation process.Part II:Mitomycin C-eluting biliary stents could be successful prepared by polylactic acid as a drug carrier. In vitro studies showed that the drug-eluting stents could sustainable and stable release of Mitomycin over30days.