Experimental Study For A New Type Anti-calcification Bovine Jugular Venous Conduit

ObjectiveTo study for a new type treatment that reduces the calcification and improves the durability of glutaraldehyde-treated bovine jugular venous c onduit, in order to develop a new type anti-calcification bovine jugular venous conduit (BJVC).Evaluation of its biomechanics performance, anti-ca lcification, anti-inflammatory performance, and biocompatibility. Preliminar y discuss the feasibility of the conduit as right ventricular outflow tra ct(RVOT) reconstruction material. Provides the basis for the next step to do generally animal experiments and enter Phase I clinical trials.MethodIn this study, carried out sequentially in 3 parts:1.New anti-calcification bovine jugular venous conduit preparation a nd biomechanics measuring:(1)New anti-calcification bovine jugular venou s conduit preparation:Fresh bovine jugular venous which hot ischemia tim e within two hours, were treated by 0.6%glutaraldehyde 24 hours, followed by 0.5%Triton X-100 48 hours and 5%epoxy chloropropane(EC) 24 hours, and presevered by 0.3%glutaraldehyde(GA). (2)Biomechanics measuring:BJVC weredivided into three groups:GA group(Material treated only by glutaraldeh yde);EC+Tr group(Material treated by glutaraldehyde, TritonX-100 and epox y chloropropane);Fresh group(fresh BJV). We measured the three groups shr inkage temperature whit our self-made shrinkage temperature meter, and me asured the maximum of tensile strength and elongation at break with Elec troForce tensile force meter.2. In vivo anti-calcification and anti-inflammatory study:Each of GA a nd EC+Tr group BJVC was cut into 8 trial patches. One of the trial patches in each groups was implanted subcutaneously in the same SD rat (total 8 r ats).All trail rats were sacrificed 8 weeks after implantation, and the sp ecimen were retrieved. The morphologic properties and inflammatory respons e of test specimen were evaluated by HE stain. The tissue calcium content was determined by flame atomic absorption spectrophotometer.3. Biocompatibility in vitro and in vivo evaluation:According to the manual of National implant materials evaluation standard, the GA and EC+ Tr group BJV extracts were subjected to biocompatibility evaluation, which included hemolysis test, intracutaneous stimulation test, general acute to xicity test and cell culture cytotoxic test.ResultsWhen compared with GA group,the EC+Tr group BJVC showed apparent adva ntages in term of its characteristics as fellow:(1)Biomechanics:①Highe r shrinkage temperature (86.15±0.92℃vs 82.73±1.28, P<0.05);②Higher te nsile strength (5.31±0.14MPa vs 4.52±0.56 MPa, P<0.05) and elongation at break%(265.1±27.8 vs 237.8±17.41, P<0.05). (2) In vivo anti-calcification and anti-inflammatory:①The tissue structure of the EC+Tr group specimen kept intact,the tissue degradation was slight and less inflammatory cell s infiltrated;②The calcium content of subcutaneous implanted specimen wa s lower(51.2±2.69μg/mg vs 73.2±3.82μg/mg, P<0.01). (3)Biocompatibility:①The rate of hemolysis was 2.6%, which was lower than the GA group 3.7%( P<0.05), conform to the national standards(<5%);②The primary irritation i ndex(PⅡ) in intracultaneous stimulation test was 0.5, lower than GA group (0.87), prompt stimulate slight;③Showed no toxicity in general acute tox icity test;④There was no obvious change of cell morphology and prolifera tion after L-929 mouse fibroblasts were treated by 100% material extracts. The RGR was 87.55%, the toxicity gradation was 1(qualified); significantly better than GA group(The RGR was 69.47%, the toxicity gradation was 2, P<0. 05).Conclusion1. The technic of Triton X-100 and epoxy chloropropane modification wi th glutaraldehyde-treated BJV, is a effective and anti-calcification way to BJVC preparation.2. Compared to only treated with glutaraldehyde,Triton X-100 and epoxy chloropropane modified BJVC has proper biomechanic property and more ex cellent anti-calcification properties.3. The Triton X-100 and epoxy chloropropane modification with glutaral dehyde-treated bovine jugular venous had good biocompatibility and was conformity with the national standards, provides the basis for clinical ap plication.