Study On Glutaraldehyde - Immobilized Bovine Jugular Vein Treated With Modified Tannic Acid

Part IObjective:To investigate effects of eight different tannic acid treatments on anti-calcification, the biomechanics and fibred structures of bovine jugular vein(BJV), and got treatment program.Methods:Fresh bovine jugular vein were treated with 0.15% or 0.3% concentration of tannic acid solution and four different duration of time (one day, two days, three days, four days). Calcium level was measured by implanting BJVs subcutaneously into the rat. The shrinkage temperature, tensile strength, elongation at break and histological changes were evaluated as well.Results:In 0.3% tannic acid for 4 days group, shrinkage temperature was maximum(95.34 ± 0.98 ℃), calcium level was minimum (21-days’2.81±2.05mg/g, 60-days’6.67±3.89 mg/g); the group of higher concentrations of tannic acid solution and longer crosslinking time could decrease elastic fibers and collagen fiber degradation; tensile strength and elongation at break were not found different in eight groups.Conclusion:The group of higher concentrations of tannic acid solution and longer crosslinking time could improve thermal stability and anti-calcification, and decrease elastic fibers and collagen fiber degradation.0.3% tannic acid for 4 days group was slected.PartIIEffect of post-treatment on tannic acid fixed bovine jugular veinObjective:To investigate effects of post-treatment on stability of storage solution/ thermostability, anti-calcification, the biomechanics and fibred structures of tannic acid fixed bovine jugular vein(BJV).Methods:Fresh bovine jugular vein were treated with glutaraldehyde (Glut group), tannic acid (TA group), and post-treatment on TA-fixed (Study group). Calcium level was measured by implanting BJVs subcutaneously into the rat. The shrinkage temperature, tensile strength, elongation at break and histological changes were evaluated as well.Results:Compared with Glut group, all results were better in Study group (P<0.05). Compared with TA group, in the Study group, color of storage solution did not change, shrinkage temperature(94.16±0.97℃ vs 96.52±0.93, P<0.01) and 60-days’ calcium level (1.56±0.50mg/g vs 2.57±0.70 mg/g, P<0.01) decreased,21-days’ calcium level (1.47±0.25mg/gvs 1.06±0.24 mg/g, P<0.01) increased; biomechanical properties were not statistics difference between TA group and Study group (P> 0.05), and collagen fibers and elastic fibers were maintained well in TA group and Study group.Conclusion:Post-treatment on TA-fixed Bovine Jugular Vein can improve stability of storage solution and BJVs elasticity, and do not change anti-calcification, biomechanical properties and fibred structures of TA-fixed BJVs.Part IIIHemodynamic and histological performances of post-treatment on tannic acid fixed bovine jugular vein conduit for right ventricular out flow tract reconstruction in sheep modelObjective:To investigate effects of Hemodynamic and histological performances of post-treatment on tannic acid fixed bovine jugular vein conduit for right ventricular out flow tract reconstruction in sheep model.Metheds:Fresh bovine jugular vein were treated with glutaraldehyde (Glut group) or post-treatment on TA-fixed (Study group), and then were implanted in RVOT position of six sheep (2 for Glut group and 4 for Study group). After 140 days the conduits were explanted. PA pressure gradients, flow velocity, echocardiography and CT imaging were performed. Calcium level was measured and histological changes were evaluated as well.Results:One animals (Study group) died of right heart failure after 4 days’ post-operation. Tow animals (Study group) died of endocarditis. The remaining sheep survived until sacrifice. At completion of implantation, the conduits of two groups performed similarly with PA pressure gradients, flow velocity and echocardiography study. The conduit was found calcification in CT imaging, and elastie fiber degeneration in Glut group. In Study group, however, the conduit calcification was not detected and wall structure were maintained well. Additionally, Glut group’s calcium level were higher than TA group’s.Conclusion:Post-treatment on tannic acid fixed bovine jugular vein not only showed good hemodynamic performance, and protected fibred structures, but also improved anti-calcification in the sheep RVOT position.