Study Of The Effects Of V.A.C On Wound Edema And Microenvironment Of Chronic Would

Wound healing, chronic wound healing in particular, is one of the important subjects in surgical field. Researchers have been doing a lot of work on the study of the pathology, pathophysiology, mechanism of formation, as well as treatment of chronic wound and made some progress. The vacuum assisted closure(V.A.C)is a new method for wound control and treatment . The studies of Xu-L-S had showed that V.A.C could decrease bacterial colonization, stimulate growth of granulation tissue, enhance re-epithelialization, and improve microcirculation. In addition, V.A.C could improve the survival rate of skin graft or skin flap and showed matchless superiority in clinical application. We observed that wrinkles occur in the skin around wound and the edema attenuate markedly after treatment with V.A.C, but the mechanisms of V.A.C improving wound healing are not well understood. In this experiment, we studied the effect of the V.A.C on edema, vessel permeability and microenvironment of wound. An acute skin wound model of rabbit ear was used to examine the effects of V.A.C on edema and vessel permeability of the wound by wet-dry subtraction and Evans-Blue(EB) staining. From six patients with chronic wound treated with V.A.C, wound fluid and tissue on edge of wound were collected before treatment and 4,8-day after treatment respectively. The level of EGF and bFGF in tissue of wound edge was analyzed by immunohistochemistry ; the effects of CWF on proliferation and cell cycle of dermal fibroblasts was studied by cell culture.Result: (1) Compared with control group, the content of tissue water in the treatment group decreased significantly after 2-days treatment (69. 4%±0. 8%vs72. 5%±0. 8%, P<0.01) .The same result was obtained in the 4,6,8-day treatment groups. (2) Compared with the paired control groups (18. 0±0. 6μg/g, 14. 9±0. 6 μg/g, 10. 9±0. 4μ g/g), the EB concentration in tissue of 4,6,8-day treatment groups (15. 9±1. 2μg/g, 11. 9±0. 6μg/g, 7. 0±0. 6μg/g) decreased markedly(P<0.01). (3) The analysis of the immunohistochemical section showed a significantly increased expression of EGF and bFGF in wound edge after 8-day treatment (+~++VS++~+++,P<0.05) . (4) Cell counter demonstrated that the cell number of before treatment group was (9.58 ± 2.29)×104, those of 4-day and 8-day treatment groups were (14.58±4.01)×104, (21.67 ± 3.14) × 104 respectively. Compared with before treatment group, the number of dermal fibroblasts in treatment groups increased significantly (p<0.01).(5) The cell cycle analysis demonstrated the similar result. Conclusions :(1 )The vessel permeability and edema around wound can be efficiently counteracted by V. A. C. (2) The level of EGF and bFGF in tissue of wound edge increased by V.A.C. (3) The microenvironment of wound was changed by V.A.C and the wound fluid collected after treatment by V.A.C stimulated proliferation of dermal fibroblasts.