Shiqiang Liu1, Jianke Ding1, Yu Zhang1, Xiaoxi Cheng1, Chen Dong1, Yajuan Song1, Zhou Yu2, Xianjie Ma3. 1. Department of Plastic Surgery, Xijing Hospital, Air Force Medical University, Xi'an, Shaanxi Province, China. 2. Department of Plastic Surgery, Xijing Hospital, Air Force Medical University, Xi'an, Shaanxi Province, China. Electronic address: yz20080512@163.com. 3. Department of Plastic Surgery, Xijing Hospital, Air Force Medical University, Xi'an, Shaanxi Province, China. Electronic address: majing@fmmu.edu.cn.
Abstract
BACKGROUND: Despite its increasing use, not much is known about tissue expansion, and its complication rates are significantly high. Thus, there is an urgent need to establish a stable animal model to overcome the limitations and complications of tissue expansion. Although the mouse model has shown several advantages in the in-depth studies, an appropriate mouse expansion model has rarely been reported, likely because of its loose skin. MATERIALS AND METHODS: A micro expander was designed and implanted under the scalp of a mouse (expanded group); sterilized saline was regularly injected into the expander. In sham-operated mice (control group), a silicone sheet was implanted under the scalp. Skin samples were collected 5 wk after surgery. Histologic changes including epidermal and dermal thickness and collagen fiber arrangement were analyzed. In addition, vascular density and cell proliferation ratio were determined. An ultrastructural analysis was also performed. RESULTS: With the application of the expansion device, the skin became tight and showed area enlargement. The epidermal thickness of the expanded skin increased significantly (P < 0.01), whereas the thickness of the dermis decreased significantly (P < 0.05) as compared with the control skin. Masson staining demonstrated that collagen bundles were arranged more compactly in the expanded skin (P < 0.05) than in the controls. Furthermore, more proliferating cells (P < 0.05) and blood vessels (P < 0.01) were observed. Transmission electron microscopy showed that the fibers of expanded skin were stretched and broken into bundles of various diameters, with abundant active fibroblasts. CONCLUSIONS: A reliable mouse model of scalp skin expansion was successfully established, which may be a promising tool for in-depth studies on skin soft tissue expansion.
BACKGROUND: Despite its increasing use, not much is known about tissue expansion, and its complication rates are significantly high. Thus, there is an urgent need to establish a stable animal model to overcome the limitations and complications of tissue expansion. Although the mouse model has shown several advantages in the in-depth studies, an appropriate mouse expansion model has rarely been reported, likely because of its loose skin. MATERIALS AND METHODS: A micro expander was designed and implanted under the scalp of a mouse (expanded group); sterilized saline was regularly injected into the expander. In sham-operated mice (control group), a silicone sheet was implanted under the scalp. Skin samples were collected 5 wk after surgery. Histologic changes including epidermal and dermal thickness and collagen fiber arrangement were analyzed. In addition, vascular density and cell proliferation ratio were determined. An ultrastructural analysis was also performed. RESULTS: With the application of the expansion device, the skin became tight and showed area enlargement. The epidermal thickness of the expanded skin increased significantly (P < 0.01), whereas the thickness of the dermis decreased significantly (P < 0.05) as compared with the control skin. Masson staining demonstrated that collagen bundles were arranged more compactly in the expanded skin (P < 0.05) than in the controls. Furthermore, more proliferating cells (P < 0.05) and blood vessels (P < 0.01) were observed. Transmission electron microscopy showed that the fibers of expanded skin were stretched and broken into bundles of various diameters, with abundant active fibroblasts. CONCLUSIONS: A reliable mouse model of scalp skin expansion was successfully established, which may be a promising tool for in-depth studies on skin soft tissue expansion.