The Preparation Of Man-made Fibric Stent And Bovine Jugular Vein Conduit Complex

Chapter One:The preparation of the complex of man made fibric stent and bovine jugular vein and the mechanic function testingObjective:To increase the mechanic characteristic of bovine jugular veins conduit(BJVC) by using man made fiber stent outside,and to improve the tissue engineering method of BJVC.Methods:Nylon and Dacron fibers were choosed to make the stent. To make a fibric stent:Firstly,a chain was sewn till become an enough length,and then connected the head and the tail together.Sew a certain mesh as wanted and then another until finish.To make a bovine jugular vein conduit without any cells inside, including:1,drawing the materials;2,getting rid of the cells according to the three steps;3,the further dealing with BJVC by photooxidation.Evaluation indexs:1,Observation in general in the color,flexibility, thickness and valve structure of BJVC.2,The observation in microscope.Results:There was no extension of the BJVCs with fibric stent under pressure of 20mmHg.The extension was＜10%under pressure of 30mm and 40mmHg,untill 60mmHg,≈10%.While extension of the simple BJVCs under the pressure of 20mmHg reach 15%,and≈42%,53%,75% when 30,40,60mmHg.The difference of the two groups above has statistics significance.The results of valve regurgitation volume sign:there was no regurgitation of the BJVCs with fibric stent under pressure of 20,30mmHg. The volume≈8ml/min when the pressure was 40mmHg,and≈84mmHg when the pressure was 60mmHg.While regurgitation volume of the simple BJVCs was 0 when 20mmHg,and≈32,113,207ml when the pressure was 30,40,60mmHg.The difference of the two groups above has statistics significance.The results of leakage:there was no leakage of the BJVCs with fibric stent till pressure of 60mmHg,the volume was 1ml/min.While leakage volume of the simple BJVCs was 1,5,13ml/min when the pressure was 30, 40,60mmHg.The difference of the two groups above has statistics significance.Conclusion:The BJVCs with fibric stent had the two advantages of BJVC and fibric stent so that it may be an ideal option of solving the mechanic insufficient of BJVC. Chapter Two:Histological and biocompatibility evaluation of bovine jugular venous conduit complex treated with decellularization andphotooxidation techniqueObjective:To investigate the histological change of the complex of fibric stent and BJVCs treated with decellularization and photooxidation technique in vivo and evaluate the possibility of which as a tissue engineering scaffold in clinical application.Methods:BJVCs treated with decelluarization and photooxidation method were implanted in young dogs to reconstruct the connection of pulmonary arteries with right ventricles.The conduits were explanted and analyzed by gross examination,light microscopy in 1 month,6 months and 1 year after being implanted.Tissue collagen was assayed respectively to the explanted tissues.Neutral salt soluble fractions,acetic acid soluble fractions and pepsin-digested fractions of collagen were extracted and assayed for these samples.Results:Of 11 dogs subjected implantation,2 died of ventricular fibrillation in operation and the other 9 ones survived.3 dogs sacrifaced in 1 month after operation,three in 3 month,3 dogs sacrifaced in 6 month.All the luminal wall were still soft and smooth without calcification, thrombosis and hemangioma.No graft stenosis was observed in all animals except that membrane-like intimal hyperplasia was found in the right-ventricle-side perianastomotic regions in one of 1-year dogs.The valves all functioned well and the thicknesses of which were not changed. Endothelium-like cells had migrated in the perianastomotic regions,and endothelium-like cells had also been found in valves and middle regions of BJVCs.Macrophages appeared in 1 month but disappeared in 6-month and 1-year dogs.Carcinogenic test:To observe the canceration number of important organs in the whole body at 18 months after operation of implanting the valved bovine jugular vein conduit patches in the body of the SD mice. And there was no irritation reaction or tumor occurred in the test animals.Conclusions:The preliminary results in vivo showed decellularizaton and photooxidation treated BJVCs complex having growth potentiality and supporting endothelialization,with low-immunogenicity and low-calcification, which surpport the conduit as a tissue engineering scaffold for reconstructing the connection of pulmonary arteries with right ventricles.