Femoral occlusion increases hypoxia‐inducible factor‐1α in dorsal root ganglion and hindlimb muscle

Abstract

Hypoxia inducible factor‐1 (HIF‐1) has an important contribution to pathophysiological changes of homeostasis under conditions of oxygen deprivation as well as ischemia. We employed western blotting methods to examine effects of femoral occlusion on protein expression of HIF‐1α in dorsal root ganglion (DRG), different fiber types of muscle i.e. oxidative and glycolytic muscle. DMOG was used to enhance HIF‐1α activity following local intramuscular injection (IM). Our data show that HIF‐1α was increased in lumbar DRG after formal artery ligation by using a rat model in different time courses as compared with sham control (3.4±0.5 vs 1.1±0.1 fold at 6 hrs; 3.1±0.4 vs 1.2±0.2 fold at 24 hrs; 2.3±0.4 vs 1.1±0.2 fold at 72 hrs; p<0.05). This effect was mimicked by IM of DMOG (5.0±0.3 vs 1.3±0.2 fold at 24 hrs, p<0.05) in lumbar DRG. In contrast, HIF‐1α outside lumbar DRG was not altered, which suggests HIF‐1α was increased due to specifically localized hindlimb. In addition, HIF‐1α was increased in both red and white muscle after femoral occlusion compared with non‐occlusion control; however, the level of HIF‐1α was greater in white muscle as compared with red muscle. In conclusion, femoral occlusion increases HIF‐1α expression in DRG, and differentially increases HIF‐1α expression in different fiber types of muscle. We anticipate that HIF‐1α is likely to contribute to autonomic responses to activation of muscle afferents.