Comparative Study Of Profibrotic Characteristics Of Dermis From Different Layers Of Pig Skin

ObjectiveTo explore the profibrotic characteristics of the autografted dermis,acellular dermal matrix(ADM),and dermal fibroblasts(DF)from superficial/deep layers of pig skinMethods(1)The superficial/deep dermis were horizontally separated from the dorsa of the female,red Duroc pig using a dermatome,and were used for: the isolation of superficial/deep DF;manufacture of superficial/deep ADM;and the establishment of wound models.Wound models autografted with the superficial/deep dermis/ADM were subjected to H&E staining for measuring the wounded skin thickness.Wound models autografted with the superficial/deep DF were subjected to H&E staining for measuring the thickness of the newly formed extracellular matrix.All the wound models were subjected to western blot analysis(WB)for the quantitative analysis of alpha-smooth muscle actin(?-SMA);(2)The ultrastructure and surface morphology of the superficial/deep DF were examined by electron microscope.The superficial/deep DF were also subjected to immunocytochemical staining,the hydroxyproline assay kit,the WB,and the real-time polymerase chain reaction(real-time PCR).Results(1)The H&E staining showed that the wound models autografted with the deep dermis were significantly thicker than those of the superficial ones,the wound models autografted with the deep ADM were significantly thinner than those of the superficialones,and the newly formed extracellular matrix in wound models autografted with the deep DF was significantly thicker than those of the superficial ones;(2)The electron microscope showed that the superficial/deep dermis,ADM,and the DF exhibited distinct morphological characteristics.The immunocytochemical staining showed that the positive rate of ?-SMA in the deep DF was higher than that of the superficial one;(3)The WB showed that the wound models autografted with the deep dermis/DF exhibited higher ?-SMA expression than those of the superficial ones,conversely,the wound models autografted with the superficial ADM exhibited higher ?-SMA expression than those of the deep ones.The in vitro study also showed that the deep DF exhibited higher ?-SMA expression than the superficial one;(4)The hydroxyproline assay showed that the deep DF produced significantly more collagen compared to the superficial one.The real-time PCR showed that the mRNA level of either the ?-SMA or the procollagen type ? in the deep DF were higher than those of the superficial one.ConclusionsThe deep dermis and DF exhibited more profibrotic characteristics than the superficial ones,on the contrary,the deep ADM exhibited less profibrotic characteristics than the superficial one.Similar to human DF,deep and superficial DF of the female,red Duroc pig were also heterogeneous in either the profibrotic characteristics or the morphological characteristics.