Pharmacological investigation on the wound healing effects of Radix Rehmanniae in an animal model of diabetic foot ulcer

Ethnopharmacological relevance: Radix Rehmanniae (RR) has a very long history of usage in traditional Chinese medicine and is usually one of the principal herb found in many herbal formulae used in diabetic foot ulcer. Aim of the study: RR aqueous extract was investigated for its wound healing effects in a diabetic foot ulcer rat model and its detailed mechanism of actions. Materials and methods: A previously established diabetic foot ulcer rat model was used to assess the effect of RR extract on wound area reduction, tissue regeneration and angiogenesis. Carrageenan-induced inflammation rat model was used for inflammation study; and diabetic control was evaluated using a neonatal streptozotocin-induced diabetic rat model. Results: In the RR treated group, a trend of reduction of the wound area was observed from days 8 to 18 and a significant difference (as compared with control group) was found on day 8. The ulcer healing effect of RR extract was further supported by better developed scars and epithelialization as well as good formation of capillaries with enhanced VEGF expression. Carrageenan-induced inflammation was also significantly alleviated with RR extract. Conclusions: Our results demonstrated for the first time that Radix Rehmanniae was effective in promoting diabetic foot ulcer healing in rats through the processes of tissue regeneration, angiogenesis and inflammation control, but not glycemia control. The present study provided scientific basis to support the traditional use of Radix Rehmanniae in diabetic foot ulcer. (C) 2009 Elsevier Ireland Ltd. All rights reserved.