Comparative Study On The Biological Characteristics Of Porcine And Human Acellular Dermal Matrix

Allogenic ADM has been widely used in the treatment of severe burn, but its source and ethical acceptability always limit its application. Due to the similarities on the structure and composition of porcine skin to that of human, porcine ADM provides a possible alternative substitute for human ADM. However, porcine ADM remain some antigenicity even though after removing the cellular component and dermal appendages. A synthetic comparison of human ADM and porcine ADM is required to find the main factors determining the antigenicity and thereby to produce more suitable porcine ADM for wound treatment.This paper performed primary comparisons between human and porcine ADM which derived from BaMa miniature pig on histological structure, ultra-structure, protein composition, biocompatibility and their performance in treating wound after grafted onto the wounds of rats.Result: 1. Porcine ADM displayed significant similarities to that of human on the collagen structure. SDS-Dispase treatment was able to remove cells and appendant organs thoroughly with no damages to the collagen structure, therefore the human and porcine ADM samples were prepared by SDS-Dispase treatment. We found that the scaffold structure, collagen arrangement and collagen structure of human ADM was almost the same to that of porcine except for a slight difference in their black and white bands.2. Immunohistochemical staining of porcine ADM was performed using human antibodies against collagen I, collagen III, collagen IV, fibronectin, laminin and vimentin. The antibodies mentioned above were all capable of binding the porcine counterparts of their respective targets, further suggesting that the porcine ADM shares significant structural similarities to that of human.3. We analyzed the protein composition of both human and porcine ADM, by pepsin digestion and liquid nitrogen grinding-extraction. The result of SDS-PAGE indicated the main protein components of porcine ADM were of the same molecular weight as those of human.4. The biocompatibility was tested by cytotoxicity and immunogenicity test. Immunogenicity examination was performed by mixed ADM protein-lymphocyte reaction (MAPLR) (n=7), and cytotoxicity test was performed by co-culturing ADM with human fibroblasts and extraction co-culturing with human fibroblasts (ECHF) (n=5). Neither of the results of the two tests showed significant difference (P>0.05) between the human and porcine ADM groups.5. The two kinds of ADMs were used to cover full-thickness wound of Wistar rats. Result indicated that inflammatory reaction to BAMA miniature pig ADM was stronger than that to human ADM. Also, Vascularization and fibroblasts immigration in porcine ADMs was slower than those in human ADMs. However, shrink rate exhibited no remarkable difference between the two groups.Conclusion: There was strong similarity on the histological structure, ultrastructure, protein components and biocompatibility between porcine and human ADM, except a difference on grafting. A deep comparison of protein components between porcine and human ADM by bioinformatics and proteomics techniques is needed, that might be able to solve the problem of grafting rejection and substitute for human ADM in the future.