Topical application of curcumin regulates the angiogenesis in diabetic-impaired cutaneous wound

Diabetic wound characterizes with a delayed repair as a result of the lack of neoangiogenesis and the excess of inflammation. Natural products such as curcumin have shown great promises in their regulatory potentials on inflammation and angiogenesis. However, natural agents have several shortages in their bioavailability and stability when used in vivo. In this study, we have evaluated the efficacy of a topical formulation of curcumin in the enhancement of diabetic wound repair. Streptozocin-induced diabetic mice were wounded, and cream of curcumin (1%) was applied topically to wounds twice daily for different treatment periods. Inflammation, neoangiogenesis, and re-epithelialization were evaluated in each experimental group. Wounds of animals treated with curcumin showed an enhanced neoangiogenesis. Application of topical curcumin also increased the expression level of RelA as the main subunit of the nuclear factor-κB (NF-κB) signalling pathway. However, no significant effects on macrophage polarization and re-epithelialization were observed in the curcumin-treated animals. Our study using a higher concentration of curcumin in the form of a topical cream further confirmed the efficacy of curcumin as an angiogenesis-promoting agent; however, it also conveyed uncertainty over the claimed regulatory effects of curcumin on inflammation. SIGNIFICANCE OF THE STUDY: Diabetes results in several complications such as impaired cutaneous wound repair. Excess of inflammation and lack of angiogenesis are among the main causes of delayed healing in diabetes. Curcumin is famous for its anti-inflammatory properties. However, when in the body curcumin has shown to have a limited benefit unless in high-dosage consumes. This is because of its poor absorption from digestive system and its bioavailability. In this study, we have used a topical formulation of curcumin at a relatively high concentration to enhance the healing of a diabetic wound in an animal model of diabetes. We also have studied different cellular and molecular mechanisms by which curcumin may help the wound repair. Our results re-emphasize the proangiogenic potential of curcumin in diabetic wound environment.