Investigation on contraction mechanism of expanded tissue / 中华整形外科杂志

<p><b>OBJECTIVE</b>To investigate the contraction mechanism of expanded tissue.</p><p><b>METHODS</b>White domestic pigs were employed to establish tissue expansion model. Tissue samples were taken after expansion for contraction measurements and histopathological observation.</p><p><b>RESULTS</b>Dermis and capsule were the main positions of contraction. In the dermal layer, elastic fibers and myofibroblasts proliferated greatly and alpha-Actin enhanced in the myoepidermal cells and capillary endothelial cells during expansion. In the capsule, the direction of elastic and collagen fibers arranged crossly and formed into special contractible structure.</p><p><b>CONCLUSION</b>Elastic fibers, myofibroblasts and alpha-Actin enhancement of cells were the substantial materials of tissue contracture increases. The results suggest that suitable tension must be applied into expanded flaps for anti-contraction.</p>

Comparison of ultrastructural changes of skin between continuous tissue expansion and conventional tissue expansion / 中华整形外科杂志

<p><b>OBJECTIVE</b>To observe the ultrastrual changes of the skin between the continuous tissue expansion and the conventional tissue expansion.</p><p><b>METHODS</b>Twelve white piglets were used for this study on an animal model of tissue expansion with the continuous tissue expansion group and the conventional tissue expansion group. The tissue samples in each group were harvested and prepared for the transmission electron microscope observation.</p><p><b>RESULTS</b>The interspace among basal cells and spinose cells was increasing and the numbers of cell conjunctures were decreasing in the both groups. However, these changes in the continuous tissue expansion group were more obvious than in the conventional tissue expansion group. In the dermal layer of the skin, the ultrastructure of collagen fibers were basically normal. But, the fibroblasts and capillary endothelia cells were more activated in the continuous tissue expansion group, compared with the conventional tissue expansion group. The fibroblast apoptosis and collagenolysis spots were observed in both of the groups, while the red blood cells were also found in the tissue leaked outsides from the blood vascular cavities.</p><p><b>CONCLUSION</b>Tissue expansion may result in tissue growth and tissue degeneration in the same time.</p>