The effects of melatonin on open wounds of aged mice skin

Objective. To study the effects of melatonin on open wounds of aged mice skin by morphological and morphometric evaluations. Forty 16-month-old male Suri mice were used for this study. They were divided into two groups: 20 mice for control and 20 mice for the experimental group. Under ether anesthesia, the hair on the back of the neck of the two groups was shaved and a 2-cm long, full-thickness incision was made and left unsutured. The experimental group was injected intraperitoneally with a daily single dose of 10 mg/kg melatonin in saline for a total period of 12 days, while the control group received only saline for the same period of time. The mice of experimental and control groups were sacrificed on days 9 and 12 after making the incision, and the skin in the area of the incision was dissected and processed for light microscopy analysis. The epithelization, the mean diameter of nucleus in fibroblasts, the level of hydoxyproline, and the amount of collagen fibers were evaluated. Statistical analysis was performed using SPSS software and Mann- Whitney U test to assess the significance of changes between control and experimental groups. The dissected skin from the experimental group 9 and 12 days after making the incisions showed a significant increase of mean diameter of nucleus in fibroblasts (P < 0.001). The epithelization, the amount of collagen fibers, and the level of hydroxyproline were also increased significantly compared to control group (P < 0.001). The results of this study suggest that melatonin may be beneficial to the healing process of open wounds in aged mice. .