Effects of PEMF on microcirculation and angiogenesis in a model of acute hindlimb ischemia in diabetic rats.

Hindlimb ischemia is a major complication of diabetic patients due to poor neovascularization. Therapy with pulsed electromagnetic fields (PEMF) can promote angiogenesis in ischemic lesions. However, the efficacy and therapeutic mechanisms of PEMF in diabetes-related hindlimb ischemia are unclear. Sprague-Dawley rats were injected with streptozocin to induce diabetes, and 10 weeks later diabetic rats were subjected to surgical induction of acute hindlimb ischemia. The rats were randomized and treated with PEMF, and the blood perfusion of individual rats was determined longitudinally by laser Doppler perfusion imaging (LDPI). The neovascular density was examined using immunofluorescent analysis of CD31 expression and alkaline phosphatase (AP) staining. The levels of VEGF, VEGFR, FGF-2, and FGFR1 expression, and ERK 1/2 and P38 phosphorylation in the muscles were characterized using enzyme-linked immunosorbent assay (ELISA) and Western blot assays. The values of LDPI in the PEMF-treated rats at 14 and 28 days post surgery were significantly greater than those in the controls, accompanied by significantly elevated levels of anti-CD31 and AP staining. The relative levels of FGF-2 and FGFR1, but not VEGF and VEGFR expression, and ERK1/2, but not P38 phosphorylation, in the muscles of the PEMF-treated rats were significantly higher than those in the controls. Our data indicated that PEMF enhanced acute hindlimb ischemia-related perfusion and angiogenesis, associated with up-regulating FGF-2 expression and activating the ERK1/2 pathway in diabetic rats. Therefore, PEMF may be valuable for the treatment of diabetic patients with ischemic injury.