EFFECTS OF SYSTEMIC ADMINISTRATION OF ESTROGEN ON THE PROCESS OF WOUND HEALING IN EXCISIONAL WOUNDS IN DIABETIC RAT

Different factors such as hypoxia, nutrient deficiency and metabolic disorders (diabetes mellitus) are known to disturb wound healing process. Previous studies have shown that systemic and local administration of estrogens promote tissue repair through alteration of inflammatory responses, down regulating of macrophage migration inhibitory factor (MMIF) and particularly release of growth factors. Estrogens have potent effects on angiogenesis by stimulating the endothelial cell migration and proliferation. The aim of the current study was to evaluate the effects of systemic administration of estradiol on the process of wound healing in excisional wounds of diabetic rat. Forty four male Sprague Dawley rats (N) were divided into four groups (2 normal and 2 diabetic groups). Diabetes was induced by Streptozotocin (STZ) administration (38mg/kg, IV). In one normal and one diabetic group estradiol valerate (200ųg/kg, IM.) was injected 24 hours before wounding. Control groups received same volume of vehicle (season oil). The rats received four full thickness excisional (6 mm in diameter) wounds (n) in paravertebral region on the back. Wound size was monitored and measured at days 1, 4, 8 of wounding. The surface area and the rate of size reduction were determined accordingly. To digitalize the wound size, wound images were scanned imported to a PC and analyzed by ScnImage software. Repaired tissue was harvested on day 10, post wounding. Also wound-healing qualities were evaluated by microscopic examination of the section prepared from harvested tissues. Administration of estradiol significantly increased the rate of wound size reduction, both in normal (P<0.05) and diabetic rats (P<0.05) compared with their control groups. Histological evaluation showed that angiogenesis and cell population was positively affected by estradiol in normal and diabetic repaired tissue. Systemic administration of estradiol 24 hours before wounding improved the wound healing in normal and diabetic wounds.