OBJECTIVETo investigate the contraction mechanism of expanded tissue.

METHODSWhite domestic pigs were employed to establish tissue expansion model. Tissue samples were taken after expansion for contraction measurements and histopathological observation.

RESULTSDermis 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.

CONCLUSIONElastic 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.