Experimental study on long-term outcome of porcine collagen membrane xenotransplantation in vivo

Abstract

To observe the long-term outcome and biocompatibility of the porcine collagen membrane (DermalGen) after xenotransplantation in vivo. Twenty Sprague Dawley rats were randomly divided into 2 groups ( n=10). DermalGen were implanted subcutaneously into the dorsum of rats in experimental group, and the rats in control group were treated with sham-operation. At 3, 7, and 15 days and 1, 3, 6, and 12 months after operation, the samples of experimental group were harvested and gross observation, histological observation, CD31 immunohistochemical staining, and transmission electron microscope observation were taken to observe the inflammatory reaction, angiogenesis, and collagen arrangement. The skin tissues of the control group at 12 months were observed and compared. All incisions healed in experimental group, without obvious swelling and inflammatory reaction. The DermalGen was closely contact with the surrounding tissue without obvious rejection, and it was still legible at 12 months. Histological observation of experimental group showed that the infiltration of fibroblasts and inflammatory cells were seen at 7 days. More capillaries and fibroblast cells were seen and the inflammatory response gradually faded at 15 days and 1 month. There were abundant vessels and cells in the DermalGen at 3 months. The angiogenesis and fibroblasts decreased gradually, and the collagen started to format and margin blended simultaneously at 6 and 12 months. The inflammatory cells in experimental group at 15 days and 1 month were significantly more than that in control group ( P<0.05), and no significant difference was found at 12 months between experimental group and control group ( P>0.05). Immunohistochemical staining of experimental group showed that the angiogenesis changed obviously with the time, and the density of vessels decreased significantly at 12 months. Compared with control group, the possitive expressions of CD31 in experimental group at 15 days and 12 months after operation were significantly decreased ( P<0.05), and were significantly increased at 1 month ( P<0.05). Transmision electron microscope observation showed that the arrangement of collagen in grafted DermalGen had no obvious changed when compared with the DermalGen, and vascular endothelial cell, capillarypericytes and fibroblast cells could be seen inside. The DermalGen structure is stable after long-term xenotransplantation and with good tolerogenic property in vivo.