摘要
Objective To develop a new vascular xenograft and to compare the in vivo behavior of thrombogenicity and intimal hyperplasia in the heparin-treated and the non-heparin-treated decellularized xenografts.Methods Canine common carotid arteries were decellularized by enzymatic and detergent extraction procedures.Then a part of decellularized vascular grafts were covalently linked with heparin.Xenografts with(n=24)and without(n=24)heparin treatment were implanted in rabbits' left and right carotid artery respectively as bypass grafts.Graft patency were checked by Duplex ultrasonography at 3 and 6 months after implantation.Twelve rabbits were euthanized randomly at 3 and 6 months respectively and bilateral grafts were explanted.Histological examination and immunohistochemical staining were performed to observe the vascular remodeling.The efficiency of heparin release was demonstrated with toluidine blue staining.HE staining and micrograph analysis system were used for valuating the intima hyperplasia(IH)of bilateral grafts.Results During implantation,thrombosis rate was 4% in the heparin-treated xenografts and 25% in the non-heparin-treated xenografts after 3 weeks(P<0.05).After 6 months,it was 8% versus 58% respectively(P<0.01).Both xenografts of two groups harvested at the end of 3 or 6 months showed a satisfactory cellular reconstruction of either smooth muscle cells or endothelial cells.Intimal hyperplasia in the heparin-treated vascular was less than in the non-heparin treated xenografts.In addition,intimal hyperplasia was liable to appear close to the proximal and distal anastomotic stoma.Toluidine blue staining demonstrated that heparin was slowly released during 6 months.Conclusion This study provides a new strategy to develop a small-caliber vascular xenograft through enzymatic-detergent extraction and heparin treatment.Heparin treatment of the decellularized xenograft is helpful for improving bypass graft patency and reducing intimal hyperplasia.If there was no thrombus,bilateral bypass grafts will undergo a vessel remodeling procedure.Canine common carotid artery treated by detergent and enzymatic extraction and heparin treatment may be used as a new small-caliber vascular xenograft.
Objective To develop a new vascular xenograft and to compare the in vivo behavior of thrombogenicity and intimal hyperplasia in the heparin-treated and the non-heparin-treated decellularized xenografts. Methods Canine common carotid arteries were decellularized by enzymatic and detergent extraction procedures. Then a part of decellularized vascular grafts were covalently linked with heparin. Xenagrafts with （ n = 24） and without （n = 24） heparin treatment were implanted in rabbits＇ left and right carotid artery respectively as bypass grafts. Graft patency were checked by Duplex ultrasonography at 3 and 6 months after implantation. Twelve rabbits were euthanized randomly at 3 and 6 months respectively and bilateral grafts were explanted. Histological examination and immunohistochemical staining were performed to observe the vascular remodeling. The efficiency of heparin release was demonstrated with toluidine blue staining. HE staining and micrograph analysis system were used for valuating the intima hyperplasia （1H） of bilateral grafts. Results During implantation, thrombosis rate was 4% in the heparin-treated xenografts and 25% in the non-heparin-treated xenografls after 3 weeks （ P 〈0. 05）. After 6 months, it was 8% versus 58% respectively （ P 〈 0. 01 ）. Both xenografls of two groups harvested at the end of 3 or 6 months showed a satisfactory cellular reconstruction of either smooth muscle cells or endothelial cells. Intimal hyperplasia in the heparin-treated vascular was less than in the non-heparin treated xenografls. In addition, intimal hyperplasia was liable to appear close to the proximal and distal anastomotic stoma. Toluidine blue staining demonstrated that heparin was slowly released during 6 months. Conclusion This study provides a new strategy to develop a small-caliber vascular xenograft through enzymatic-detergent extraction and heparin treatment. Heparin treatment of the decellularized xenografi is helpful for improving bypass graft patency and reducing intimal hyperplasia. If there was no thrombus, bilateral bypass grafts will undergo a vessel remodeling procedure. Canine common carotid artery treated by detergent and enzymatic extraction and heparin treatment may be used as a new small-caliber vascular xenografi.
