| Objective: To explore the relationship between blood flow and wound healing process, and to clarificate the regulatory role of vascular endothelial growth factor (VEGF) on formation of blood vessels after scald injury in rats. Partial thickness scald on the back in rats was used as animal model. The morphological and functional changes of endothelial cells and the expression and distribution of VEGF was investigated.Methods: 54 Wistar rats were randomly divided into scald injured group (group A, 42 rats) and blood flow detecting group (group B, 12 rats). Group A was further divided into7 subgroups according to the postburn period, which were immediately after scald, 1, 3, 7, 14 and 21 days after scald and normal control. Animals were anesthesed, and then partial thickness scald (70℃, 8 seconds) was made on either side of back by using a metal scald machine. Scald injured rats were sacrificed at different time points and specimens were collected, fixed in 10% formalin. Expression levels of VEGF was determined by immunohistochemistry techniques. Results were analysed statistically after computer scanning. Results:1 Deep II degree scald could be made in rats with 70℃, 8 seconds management. Hcmatoxylin and eosin (HE) staining showed that nucleus in epidermis shrinked and accompanied with strong stain. Cell membranes were disappeared and cell necrosis was found. In dermis, necrosis of hair follicles and sebaceous glands and deformed hair follicles were observed. Epithelium cell nucleus of hair follicles became long and narrow. Collagen fibers coagulated to bundles or balls, its acidophil staining abilities declined. There were only a few skin appendages in deep dermis.2 The changes of blood flow during the healing process after deep II degree scald injury showed remarkably stage-dependent characteristics. Blood flow decreased dramatically immediately after thermal injury, which was about 51% of the normal... |
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