Single Intraosseous Injection of Simvastatin Promotes Endothelial Progenitor Cell Mobilization, Neovascularization, and Wound Healing in Diabetic Rats.

BACKGROUND

This study explored the effect of a single local intraosseous application of a small dose of simvastatin on the wound healing process in type 1 diabetic rats and related mechanisms.

METHODS

The authors chose the streptozotocin-induced type 1 diabetic rat to establish a full-thickness dermal wound using a 12-mm-diameter sterile disposable punch. The rats (n = 32) were divided randomly into four groups: (1) normal control rats, (2) type 1 diabetic rats with intraosseous injection of hydrogel vehicle, (3) type 1 diabetic rats with intraosseous injection of simvastatin (0.5 mg), and (4) type 1 diabetic rats with intragastric administration of simvastatin (20 mg/kg per day). Wound closure was followed by digital planimetry. Mobilization of endothelial progenitor cells into the circulatory system was studied using fluorescence-activated cell sorting. Neovascularization was analyzed with immunofluorescence histochemical staining. The relative levels of adiponectin and stromal cell-derived factor 1 (SDF-1) in serum, bone, and wound tissues were examined by enzyme-linked immunosorbent assay and Western blot.

RESULTS

Diabetic rats exhibited impaired wound healing. Intraosseous administration of simvastatin accelerated wound healing beginning at day 4, and angiogenesis was more obvious than in the control group. Enzyme-linked immunosorbent assay revealed that adiponectin concentrations in the diabetic rats with intraosseous injection of hydrogel vehicle plus simvastatin 0.5-mg group were significantly higher compared with the diabetic rats with intraosseous injection of hydrogel vehicle group beginning at day 4. Intraosseous administration of simvastatin decreased the expression of adiponectin and SDF-1 in bone tissue but enhanced the expression of adiponectin in wounded skin.

CONCLUSIONS

A single local intraosseous application of simvastatin promotes wound healing in type 1 diabetic rat. The underlying mechanisms may be attributed to the regulation of the adiponectin/SDF-1 pathway, which plays a pivotal role in endothelial progenitor cell mobilization and angiogenesis.