Short term supplementation of dietary antioxidants selectively regulates the inflammatory responses during early cutaneous wound healing in diabetic mice

BACKGROUND Diabetic foot ulcers are serious complications for diabetic patients, yet the precise mechanism that underlines the treatment of these diabetic complications remains unclear. We hypothesized that dietary antioxidant supplementation with vitamin C, combined either with vitamin E or with vitamin E and NAC, improves delayed wound healing through modulation of blood glucose levels, oxidative stress, and inflammatory response. METHODS Diabetes was induced by administration of alloxan monohydrate. Mice were divided into 4 groups; CON (non-diabetic control mice fed AIN 93 G purified rodent diet), DM (diabetic mice fed AIN 93 G purified rodent diet), VCE (diabetic mice fed 0.5% vitamin C and 0.5% vitamin E supplemented diet), and Comb (diabetic mice fed 0.5% vitamin C, 0.5% vitamin E, and 2.5% NAC supplemented diet). After 10 days of dietary antioxidant supplementation, cutaneous full-thickness excisional wounds were performed, and the rate of wound closure was examined. TBARS as lipid peroxidation products and vitamin E levels were measured in the liver. Expression levels of oxidative stress and inflammatory response related proteins were measured in the cutaneous wound site. RESULTS Dietary antioxidant supplementation improved blood glucose levels and wound closure rate and increased liver vitamin E, but not liver TBARS levels in the diabetic mice as compared to those of the CON. In addition, dietary antioxidant supplementation modulated the expression levels of pIκBα, HO-1, CuZnSOD, iNOS and COX-2 proteins in the diabetic mice. CONCLUSIONS These findings demonstrated that delayed wound healing is associated with an inflammatory response induced by hyperglycaemia, and suggests that dietary antioxidant supplementation may have beneficial effects on wound healing through selective modulation of blood glucose levels, oxidative stress, and inflammatory response.