Expression of miR-217 and HIF-1α/VEGF pathway in patients with diabetic foot ulcer and its effect on angiogenesis of diabetic foot ulcer rats

Objective To investigate the expression of miR-217 and HIF-1 alpha/VEGF pathway in patients with diabetic foot ulcer (DFU) and its effect on angiogenesis in DFU rats. Methods The serum levels of miR-217, HIF-1 alpha and VEGF were detected in DFU and simple diabetes mellitus (DM) patients, and healthy controls. DFU rat models were established and treated with miR-217 inhibitors and/or HIF-1 alpha siRNA. The ulcer healing of DFU rats was observed. Besides, ELISA method was performed to detect the serum level of HIF-1 alpha, VEGF and inflammatory factors, immunohistochemical (IHC) method to test the micro-vessel density (MVD), as well as qRT-PCR and Western blot to determine expressions of miR-217, HIF-1 alpha, VEGF, VEGFR2, eNOS, MMP-2, and MMP-9 in tissues. Results The serum levels of miR-217 were up-regulated while HIF-1 alpha and VEGF were down-regulated in DFU patients and rats when compared with DM and healthy controls (all P < 0.05). Dual-luciferase reporter gene assay confirmed that HIF-1 alpha was the direct target gene of miR-217. DFU rats treated with miR-217 inhibitors had decreased foot ulcer area and accelerated ulcer healing, with significantly reduced inflammatory factors (IL-1 beta, TNF-alpha and IL-6), as well as elevated HIF-1 alpha and VEGF (all P < 0.05); meanwhile, they remarkably increased the MVD in foot dorsum wound tissues and the protein expressions of HIF-1 alpha, VEGF, VEGFR2, eNOS, MMP-2, and MMP-9 (all P < 0.05). Conclusion Inhibiting miR-217 could up-regulate HIF-1 alpha/VEGF pathway to promote angiogenesis and ameliorate inflammation of DFU rats, thereby effectively advancing the healing of ulcerated area.