An extract of the root of Lithospermun erythrorhison accelerates wound healing in diabetic mice

Many people suffer from intractable bedsores, which sometimes develop because of chronic metabolic failure in patients. An extract of the root of Lithospermun erythrorhison (SK) has been reported to have an effect on wound healing. However, the effects of SK have not been studied in chronic wounds, such as bedsores. The healing-impaired diabetic (db/db) mouse is a good model for the investigation of clinical healing therapies. Therefore, we examined whether SK accelerates wound healing in db/db mice. Full-thickness round wounds of 6-mm diameter were created on the backs of mice. After applying SK, we covered the wound with a film dressing to keep it moist. At three weeks, wound closure was complete in SK-treated mice but not in controls. Capillary vessel number and collagen synthesis increased early in wound healing in SK-treated wounds. At this time, vascular endothelial growth factor (VEGF)-positive neutrophils had infiltrated the wound and the appearance of apoptotic fibroblasts and endothelial cells in the granulation tissue was more advanced than in the controls. Where the wound was covered with epithelium, there tended to be less infiltration of VEGF-positive cells and apoptotic cells. These results suggest that the inflammatory phase was shortened, and the proliferative and maturation phases were advanced by SK. It is known that SK also has antibacterial activity. Therefore, we conclude that SK is useful for wound healing in db/db mice, and could potentially help patients with intractable bedsores.