MicroRNA-155 Inhibition Promoted Wound Healing in Diabetic Rats

Diabetes leads to amputation in approximately 15% to 20% of patients and is associated with high morbidity and mortality. Thus, improving the quality of wound healing in this condition is essential. Diabetes is associated with acute/chronic inflammation affecting all organs especially the foot, while, inhibition of microRNA-155 (miR-155) has been reported to improve or reduce inflammatory situation. However, the role of miR-155 inhibition in promoting diabetic wound healing is not clear. To further study the potential benefit of miR-155 inhibition, a study of male Sprague-Dawley rats was conducted and diabetes was induced by injection of streptozotocin. Real-time polymerase chain reaction (PCR), hematoxylin and eosin staining and immunohistochemistry were then performed. The PCR results confirmed that miR-155 expression was lower after miR-155 inhibition on days 3, 7, and 13 (all Ps <.05). The wound healing rate between the normal glucose group (N group), diabetic PBS group (PBS group) and the topical miR-155 inhibitor group was compared. Faster healing of cutaneous wounds was observed in the miR-155 inhibitor group than in the PBS group and normal glucose group (P < .05). In addition, downregulation of inflammatory cells, including neutrophils (MPO-positive) and macrophages (CD68-positive), and upregulation of the angiogenic protein CD31 and markers indicative of fibroblast proliferation and collagen deposition, such as collagen 1, TGF-1, and -SMA, were observed. These data permit the observation that miR-155 inhibition possesses the potential to reduce inflammation in acute wounds. This property may benefit the healing of diabetic foot wounds.