Biodegradation of differently cross-linked collagen membranes in rats

Objectives: The aim of the present study was to compare the biodegradation of differently cross-linked collagen membranes in rats; Methods: Five commercially available and three experimental membranes (E) were included: (1) BioGide® (BG) (non cross-linked porcine types I and III collagen); (2) TutoDent® (TD) (non-cross-linked bovine type I collagen); (3) Ossix® (OS) (enzymatic-cross-linked bovine type I collagen); (4) BioMend® (BM) (glutaraldehyde cross-linked bovine type I collagen); (5) BioMend® Extend (BME) (glutaraldehyde cross-linked bovine type I collagen); VN(1-3) (chemical cross-linked porcine types I and III collagen). Each membrane was marked by a non-resorbable polycarbonate spacer. Four subcutaneous pouches were surgically separated on the back of 40 whistar rats under general anaesthesia. The membranes were randomly allocated in the resulting 160 pouches. Animals were sacrificed after 2, 4, 8, 16, and 32 weeks and explanted specimens were prepared for histological observation. The following parameters were evaluated: biodegradation over time, foreign body reaction, tissue integration, vascularization; Results: Highest vascularization and tissue integration was noted for BG, TD and VN(1-2); BM, BME and VN(3) showed moderate, while OS exhibited no vascularization. Subsequently, biodegradation of BG, TD, and VN(1-2) was faster than BM, BME, and VN(3). OS showed only a minute amount of superficial biodegradation. Foreign body reactions (lymphocytes, macrophages, multinuclear giant cells) were observed for all membranes examined; Conclusion: Within the limits of the present study, it was concluded that cross-linking of collagen types I and III may decrease vascularization and tissue integration which in turn may prolong biodegradation.