Multiparametric MRI as predictors for evaluating renal ischemia reperfusion injury and protective effect of Mito-TEMPO in rat model

BACKGROUND: We aimed to evaluate multiparametric magnetic resonance imaging (MRI), including blood oxygen level dependent (BOLD), arterial spin labeling (ASL), and intravoxel incoherent motion (IVIM) for noninvasively monitoring acute kidney injury (AKI) to acute kidney disease (AKD) progression following renal ischemia reperfusion injury (IRI) and the subsequent response to Mito-TEMPO (MT) therapy. METHODS: Phase 1: 42 Sprague Dawley (SD) rats (36 IRI and 6 control). Phase 2: 144 SD rats (IRI/control + MT treatment/saline, 36 per group). IRI group: left renal ischemia reperfusion procedures, control group: sham abdominal surgery. Animals underwent MRI scanning to obtain effective transverse relaxation rate (R2*), renal blood flow (RBF), apparent diffusion coefficient (ADC), pure molecular diffusion (D), perfusion-related diffusion (D*), and perfusion fraction (f) values of kidney. After sacrifice, serological and histological analysis were performed. RESULTS: All MRI parameters (R2*, RBF, ADC, D*, D, f) showed significant, time-dependent alterations following IRI compared to controls. These changes were effectively reversed by MT treatment, with most parameters recovering to near-baseline levels. CONCLUSION: BOLD, ASL, and IVIM can be used as noninvasive radiologic markers for detecting the progression from renal IRI to AKI-AKD and recovery after MT treatment.