Field direction of static magnetic fields influences kidney fibrosis progression through MAPK signaling and cell cycle alteration

Various mechanisms, including inflammation, oxidative stress, and apoptosis, are involved in the transition from acute kidney injury to chronic kidney disease (AKI-to-CKD). In this study, we aimed to determine the pathway linking acute injury and fibrosis under static magnetic fields (SMFs). Human tubular epithelial cells (hTECs) were cultured on SMF platforms (119 mT; outward vs. inward direction) for 3 days, followed by treatment with adenine and p38 mitogen-activated protein kinase (MAPK) inhibitor to verify the role of MAPK pathway. In-vivo, mice were orally administered adenine (2mg/mouse/day) for 14 days to induce tubular injury, and p38 MAPK inhibitor (iP38, 10mg/kg) was injected intraperitoneally to evaluate its therapeutic effect. Inward SMF exposure significantly increased phospho-p38 (pp38) expression compared to outward SMFs. p38 MAPK inhibition reduced G1/S arrest and oxidative stress, apoptosis, and expression of fibrosis markers under inward SMFs. Additionally, iP38 treatment alleviated inflammation and fibrosis in adenine-induced tubular nephropathy (AITN). This study revealed that SMF-related AKI-to-CKD transition progresses with the direction of SMFs affecting the severity of injury, whereas p38 MAPK inhibition attenuates SMF-induced kidney injury and prevents fibrosis.