Evaluation of Effect of Oleuropein on Skin Wound Healing in Aged Male Balb/c Mice

OBJECTIVE: Olive oil and olive leaf extract are used for treatment of skin diseases and wounds in Iran. The main component of olive leaf extract is Oleuropein. This research is focused on the effects of Oleuropein on skin wound healing in aged male Balb/c mice. MATERIALS AND METHODS: In this experimental study, Oleuropein was provided by Razi Herbal Medicine Institute, Lorestan, Iran. Twenty four male Balb/c mice, 16 months of age, were divided equally into control and experimental groups. Under ether anesthesia, the hairs on the back of neck of all groups were shaved and a 1 cm long full-thickness incision was made. The incision was then left un-sutured. The experimental group received intradermal injections with a daily single dose of 50 mg/kg Oleuropein for a total period of 7 days. The control group received only distilled water. On days 3 and 7 after making the incision and injections, mice were sacrificed, and the skin around incision area was dissected and stained by hematoxylin and eosin (H&E) and Van Gieson’s methods for tissue analysis. In addition, western blot analysis was carried out to evaluate the level of vascular endothelial growth factor (VEGF) protein expression. The statistical analysis was performed using SPSS (SPSS Inc., Chicago, USA). The t test was applied to assess the significance of changes between control and experimental groups. RESULTS: Oleuropein not only reduced cell infiltration in the wound site on days 3 and 7 post incision, but also a significant increase in collagen fiber deposition and more advanced re- epithelialization were observed (p<0.05) in the experimental group as compared to the control group. The difference of hair follicles was not significant between the two groups at the same period of time. Furthermore, western blot analysis showed an increased in VEGF protein level from samples collected on days 3 and 7 post-incision of experimental group as compared to the control group (p<0.05). CONCLUSION: These results suggest that Oleuropein accelerates skin wound healing in aged male Balb/c mice. These findings can be useful for clinical application of Oleuropein in expediting wound healing after surgery.