Preparation And Experimental Study On Xeno-ADM In Vivo

Objective: To investigate the difference of xenogenic acellular dermal matrixs (ADM) treated by incubating in type I collagen or cross-linked with glutaraldehyde in compatibility and capacity for rapid vascularization and reconstruction of dermal tissue . Methods: (1) ADM was produced from swine skins treated with trypsin followed by Triton X-100. (2) type I collagen of mouse tail was extracted by 0.5mol/L acetoacetic acid. (3) Two kinds of ADM were got by being soaked with 0.02% glutaraldehyde for 5~10 min or being soaked with mouse type I collagen for 24h, then preserved at 4℃. (4) The third-passage fibroblasts obtained by trypsinization of childish foreskin were seeded on the dermal side of each kind of ADMs at a density of 2×105 cell/cm2 which were used for experiment of cytotoxicity . The fibroblasts at the same density were seeded on petri dish as a control. Each group had 9 samples. Cell count was done on the 1st , 3rd , 5th days after seeding. (5) Forty eight Balb/C mice were randomly divided into 2 groups , one group mice embedded with collagen-coated ADM on the back of skin, another group mice with cross-linked ADM. then the change of the wound healing conditions of the mice were observed periodically . (6) Six cases of each group were picked out randomly and the ADMs were taken out for HE staining, VG staining (Van Giescn's staining), vWF (von willebrand factor) immunohistochemical examination at 1, 2, 4, 8 weeks after being implanted , and the proliferation of collagen fibers and infiltration of vascular endothelia cells were detected by light and scan electron microscope. Results: 1,Experiment of cellular toxigenicity : The proliferation speed of fibroblasts seeded on the collagen-coated ADM was faster than that on the cross-linked ADM. 2,Experiment of animal implantation: In living body observation showed all the experimental mice had the hair loss in the early stage, that lasted longer time in cross-linked ADM which combined with granulation tissue formation on the back of the mice. After 4 weeks, the collagen-coated ADM embedded subcutenously has been dectected a longer degradation time and lower degree of vasularization compared to the cross-linked ADM with light and scan electron microscope. But the collagen of neodermal in the collagen-coated ADM had more natural constituents and good histological compatibility than that of cross-linked ADM , which will redound to the reconstruction of skin. Conclusion: collagen-coated ADM has good biocompatibility and the ability of regenerating dermal tissue,that can be used for the scaffold of tissue engineering skin.