Static magnetic fields alleviate diabetic nephropathy by reducing renal cell inflammation and promoting M2 macrophage polarization.

Diabetic nephropathy (DN) is one of the most severe diabetic complications, which can easily progress into irreversible and detrimental end-stage renal disease if not properly controlled. However, the effective prevention of DN progression has always remained a huge challenge. Moderate intensity static magnetic fields (SMFs), which have the advantages of non-invasive and high penetration, have shown beneficial effects in reducing blood glucose in type 2 diabetes mice in recent years. In this study, by using both db/db severe diabetic mice and high-fat diet and streptozotocin-induced moderate diabetic mice, we found that SMFs have significant effects on reducing DN compared to blood glucose control. Further analyzing the db/db mice with severe diabetes, we found that kidney inflammation, vascular abnormalities, and fibrosis were all greatly reduced. Moreover, SMFs can promote macrophages polarized into M2. In vitro cellular experiments also demonstrate the positive effects of SMFs in reducing kidney cell inflammation, as well as increasing M2 macrophage polarization by promoting F-actin assembly. Therefore, our results show that moderate intensity SMFs have great potential to be developed as a new physical modality to be used in the treatment of DN, and possibly other types of chronic kidney diseases.