[A comparative study on acellular small intestinal submucosa and acellular amnion as dressings for traumatic skin...

To compare the reparative effects between the acellular small intestinal submucosa and the acellular amnion as dressings for traumatic skin defects.

Three full-thickness skin defects, which were close to the vertebral column of the pig, were created on both sides of the dorsum. The skin defects were randomly divided into three groups. In each group, the following different materials were used to cover the skin defects: the acellular amnion in Group A, the acellular small intestinal submucosa (SIS) in Group B, and the physiological saline gauze in Group C (the control group). The specimens from the skin defects were harvested for a histological evaluation and for determination of the hydroxyproline content at 10 (2 pigs), 20 (2 pigs), and 30 days (3 pigs). We observed the healing process of the wound and its healing rate, counted the inflammatory cells, vascular endothelial cells, and proliferating cells, and determined the hydroxyproline content.

The acellular amnion in Group A and the acellular SIS in Group B adhered to the wound tightly, but they did not adhere to the dressing; when the dressing was changed, the wound did not bleed. The saline gauze in Group C adhered to the wound tightly, but when the dressing was changed, the wound bled until 22 days after operation. Under the microscope, the collagen in the tissue below the epithelium was arranged more regularly and there were fewer cells concerned with inflammation in Groups A and B than in Group C at 10, 20, and 30 days after operation. At 10, 20, and 30 days after operation, the wound healing rate was greater in Groups A and B than in Group C. The number of the inflammatory cells and the proliferating cells were greater in Group C than in Groups A and B. There was a statistically significant difference (P < 0.05), At 20 and 30 days after operation, the content of hydroxyproline was greater in Group C than in Group A and B. There was a statistically significant difference (P < 0.05). However, there was no statistically significant difference between Group A and Group B in the wound healing rate, the numbers of the inflammatory cells, vascular endothelial cells and proliferating cells, and the content of hydroxyproline (P > 0.05). There was no statistically significant difference among the three groups in the number of the vascular endothelial cells.

Compared with Group C, the wound healing rate is improved, the collagen in the tissue below the epithelium is arranged more regularly, and the inflammatory cells, bleeding, and effusion are reduced in Groups A and B. The reparative effects of the acellular amnion and the acellular small intestinal submucosa as dressings on the skin defects are almost the same.