Effect of pomegranate peel polyphenol gel on cutaneous wound healing in alloxan-induced diabetic rats

Background Pomegranate (punica granatum) belongs to the family Punicaceae, and its peel has been used as a traditional Chinese medicine because of its efficacy in restraining intestine, promoting hemostasis, and killing parasites. Pomegranate peel has been reported to possess wound-healing properties which are mainly attributed to its polyphenol extracts. The purpose of this study was to investigate the effect of pomegranate peel polyphenols (PPP) gel on cutaneous wound healing in diabetic rats. Methods Alloxan-induced diabetic rats were given incisional wounds on each side of the mid-back and then treated daily with PPP gel (polyphenol mass fraction =30%) post-wounding. Rats were sacrificed on days 4, 7, 14, and 21 post-wounding to assess the rates of wound closure, histological characteristics; and to detect the contents of hydroxyproline, production of nitric oxide (NO), and activities of NO synthase (NOS), as well as the expressions of transforming growth factor-beta 1 (TGF-beta 1), vascular endothelial growth factor (VEGF), and epidermal growth factor (EGF) in wound tissue. Results Wound closure was significantly shortened when PPP gel was applied to the wounds of diabetic rats. Histological examination showed the ability of PPP gel to increase fibroblast infiltration, collagen regeneration, vascularization, and epithelialization in the wound area of diabetic rats. In addition, PPP gel-treated diabetic rats showed increased contents of hydroxyproline, production of NO, and activities of NOS and increased expressions of TGF-beta 1, VEGF, and EGF in wound tissues. Conclusion PPP gel may be a beneficial method for treating wound disorders associated with diabetes.