Assessment of redox-related mitochondrial variations in a renal ischemia reperfusion model utilizing a multimodal approach

Abstract

Acute kidney injury (AKI) is a critical clinical condition characterized by a sudden loss of kidney function, accompanied by complex metabolic and structural changes. In this study, the early molecular and metabolic effects of AKI were investigated using an ischemia-reperfusion (IR) model. The study aims to evaluate the levels of total autofluorescent molecules, analyze diffuse reflectance spectroscopy (DRS) findings, and understand the roles of oxidative stress biomarkers and functional parameters in the kidney IR. The IR model was applied in rats, DRS data were measured in vivo from the kidney and from isolated mitochondria using a fiber optic probe. Additionally, NADH and FAD levels were assessed in serum and mitochondrial isolates using fluorescence spectrometer. Kidney function/injury parameters (creatinine, KIM-1, NGAL and L-FABP) and oxidative stress biomarkers (MDA, L-OOH, dityrosine, kynurenine, and AOPP) were analyzed. In the IR group, significant increases in NADH and FAD levels were observed in both serum and mitochondrial isolates. Oxidative stress biomarkers such as kynurenine, dityrosine, and lipid hydroperoxides also increased in the IR group. DRS analyses of mitochondrial isolates revealed a marked reduction in optical signals in the IR group, but no significant changes were detected in in vivo DRS analyses. Significant correlations were identified between functional and oxidative stress parameters in serum and mitochondria. Although not significant at the tissue, the alterations observed at the mitochondrial level demonstrate the efficacy of the DRS. This study highlights the importance of integrating optical and biochemical approaches to elucidate the effects of IR on mitochondrial-related metabolic processes.