The aim of this study was to evaluate the effectiveness of Persian oak aqueous extract on dermal wound healing in rats. 35 male Wistar rats were selected and randomly divided into five groups; then two full-thickness wounds with 10 mm in diameter were created bilaterally on the back of all animals. Negative control group treated with normal saline, positive control group treated with phenytoin cream, and three treatment groups which received 2%, 4% and 8% aqueous extract of Jaft respectively. The animals received these medicines once daily for 15 days. The state of the wound healing was evaluated using wound closure ratio, wound contraction and re-epithelialization, tensile strength, VEGF and PDGF content. Histopathological examination was also performed on repaired tissues.
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The wound area Measurement The method of measuring the wound surface is as follows: First, the animals were anesthetized and each animal was placed in a standard position on a flat surface and the wound was washed with normal saline serum. A ruler was placed next to the wound and photographed from a distance of 15 cm using a digital camera. These conditions were the same for all animals during the experiment. Then the wound surface was measured and recorded using Digimizer software. The following equation was used to calculating the percentage of wound healing: Wound Healing percentage=(A0 - At )/A0×100 Where A0 is wound area on the first day and At is wound area after time interval. Histopathological study At the end of the experiment, skin samples were collected from all animals and fixed in 10% buffered formalin. After fixing and molding tissue samples in paraffin (blocking), 5 micron thick sections were prepared by microtome and stained by Masson-trichrome method (for the detection of collagen fibers) and hematoxylin and eosin (for general morphological observations). The slides were examined semi-quantitatively using a light microscope to examine inflammation, collagen formation, epithelialization, angiogenesis, and granulation tissue formation. In the Greenhalgh scoring system, each parameter is evaluated separately. Each of the parameters is given a score of zero to 3. A score of zero means that there is no such parameter, a score of 1 has a small amount, a score of 2 has a medium and a score of 3 has a high amount of that parameter. Trichrome-Mason staining method was also used to increase the accuracy of scoring of collagen fibers. Tensile strength Measurements Tissue strength indicates the degree of tissue integrity. To measure the tissue strength, at the end of the treatment period, a part of the repaired skin was cut into a strip with a width of 5 mm and its tensile strength was measured with a tensiometer. Tensile strength was calculated using the following formula: Tensile Strength=(breaking strength (g) )/(cross-sectional area of skin 〖(mm〗^2)) Growth factors assay To measure growth factors, blood samples were taken directly from the heart at the end of the experiment under aseptic conditions. The samples were then centrifuged at 1000 rpm for 15 minutes. The isolated plasma was stored at -80 °C until the experiment. The amount of PDGF and VEGF in plasma samples was measured by ELISA method according to the manufacturer's instructions.