Acceleration of wound healing activity with syringic acid in streptozotocin induced diabetic rats

Impaired wound healing is a serious concern of uncontrolled hyperglycemia that can lead to gangrene, and even death. There is an urgent need to look for better alternative therapy because of the undesirable side effects of currently available synthetic drugs in the market. Syringic acid (SA) is a natural phenolic compound abundantly available in edible fruits and plants. In this study, wound healing activities of 2.5% and 5.0% SA were evaluated in type 2 diabetic rats using incisional wound model. SA-treated diabetic wounds showed faster rate of wound closure and epithelization with enhanced contents of hydroxyproline and protein compared to diabetic wounds. SA effectively prevents alterations in blood glucose levels, serum insulin and dyslipidemia in diabetic wound rats. The SA-treated diabetic wounds after 14 days of treatment demonstrated inhibition of pro-inflammatory response (NF-κB p65, TNF-α, IL-1β, IL-8 and IL-2) with improvement in anti-inflammatory response (IL-10), inhibited the elevated oxidative stress and decreased the concentrations of matrix metalloproteinases (MMP-2, -8 and -9) and increased the concentrations of TIMP-1 & TIMP- 2. Furthermore, the diabetic wounds were presented with an increase in expression of CD 31 and 68, growth factors (TGF-β1, collagen-I and α-SMA and VEGF) with significant improvement in collagen deposition, re-epithelialization and complete skin structure as revealed by histological analysis after treatment of diabetic wounds with SA for 14 days. Hence, the results of this study designate that SA significantly improves wound healing in diabetic rats and could be used as a potential therapy for treatment of diabetic wounds.