Therapeutic effects of oleuropein on wounded skin in young male BALB/c mice.

INTRODUCTION: Oleuropein is generally the most abundant phenolic compound in olive leaves. In this study, therapeutic effects of oleuropein were studied on wounded skin in young male Balb/c mice. METHODS: Four-month-old male Balb/c mice were randomized into 2 groups, a control and an experimental group. Under ether anesthesia, hair on the neck of mice in both groups was shaved and 1-cm long full-thickness incisions were made and left unsutured. The experimental group was injected intradermally with a daily single dose of oleuropein (50 mg/kg) for a total of 7 days. The control group received only distilled water. On days 3 and 7 post-incision, mice were sacrificed and skin around the area of the incisions were dissected and processed for hematoxylin and eosin and Van Gieson's staining. Portions of dissected tissues were also lysed and used for western blot analysis to evaluate the level of vascular endothelial growth factor (VEGF) protein expression. RESULTS: The analyses showed oleuropein reduced cell infiltration into the wound sites on day 3 and 7 postincision; however, it significantly increased collagen fiber deposition and caused faster reepithelialization when compared to the control group (P < 0.05). Furthermore, western blot analysis showed a significant increase in VEGF protein level compared to the control group (P < 0.05). CONCLUSION: In summary, oleuropein showed healing effects on wounded skin by accelerating the reepithelialization process, enhancing collagen fiber generation, and increasing the blood supply to the wounded area by upregulation of VEGF protein expression.