Preparation of an acellular dermal matrix using the freeze–thawing technique with and without γ irradiation

Introduction :An acellular dermal matrix (ADM) is a dermal substitute in which the skin is treated to remove epithelia l and dermal cellular components. Aim of the work :To compare the histological and immunohistochemical structures of ADMs prepared using the freeze–thawing technique with or without γ irradiation. Materials and methods :Twenty-one human skin specimens were used and divided into three equal groups: group I (control group), group II, in which skin specimens were subjected to three repeated freeze–thawing cycles, and group III, in which skin specimens were subjected to three repeated freeze–thawing cycles and subsequent exposure to 5000 rad γ irradiation. Skin specimens from the previous groups were examined histologically and immunohistochemically for laminin. A morphometric study was carried out for the determination of the number of cells per high-power field (hpf) in both the papillary and the reticular dermis. Results :Both methods of ADM preparation resulted in extensive extraction of cellular components with preservation of the basic dermal architecture as there was a highly significant decrease in the number of cells/hpf in both layers of the dermis in groups II and III as compared with the control group (P 0.001). However, there was further decellularization in group III as there was a highly significant decrease in the number of cells/hpf in both the papillary and the reticular dermis in group III as compared with group II (P 0.001). Immunohistochemical stain of laminin revealed preservation of the epidermal basement membrane in groups II and III. Conclusion :A combination of irradiation and a freeze–thawing technique is recommended in the preparation of ADM for efficient decellularization.