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Updated: May 18, 2026
Assessment of Mitochondrial Fission/Fusion Dynamics in Kidney Proximal Tubular Cells
Published on: November 14, 2025
In vivo multiphoton imaging of mitochondrial structure and function during acute kidney injury
Andrew M Hall1, George J Rhodes, Ruben M Sandoval
1University College London Centre for Nephrology, Royal Free Hospital, London, UK. andrew.hall@ucl.ac.uk
Abstract:
Mitochondrial dysfunction has been implicated in the pathogenesis of acute kidney injury due to ischemia and toxic drugs. Methods for imaging mitochondrial function in cells using confocal microscopy are well established; more recently, it was shown that these techniques can be utilized in ex vivo kidney tissue using multiphoton microscopy. We extended this approach in vivo and found that kidney mitochondrial structure and function can be imaged in anesthetized rodents using multiphoton excitation of endogenous and exogenous fluorophores. Mitochondrial nicotinamide adenine dinucleotide increased markedly in rat kidneys in response to ischemia. Following intravenous injection, the mitochondrial membrane potential-dependent dye TMRM was taken up by proximal tubules; in response to ischemia, the membrane potential dissipated rapidly and mitochondria became shortened and fragmented in proximal tubules. In contrast, the mitochondrial membrane potential and structure were better maintained in distal tubules. Changes in mitochondrial structure, nicotinamide adenine dinucleotide, and membrane potential were found in the proximal, but not distal, tubules after gentamicin exposure. These changes were sporadic, highly variable among animals, and were preceded by changes in non-mitochondrial structures. Thus, real-time changes in mitochondrial structure and function can be imaged in rodent kidneys in vivo using multiphoton excitation of endogenous and exogenous fluorophores in response to ischemia-reperfusion injury or drug toxicity.
Insights
This study demonstrates real-time in vivo imaging of kidney mitochondrial function in rodents. Multiphoton microscopy visualizes mitochondrial changes during acute kidney injury from ischemia or drug toxicity.
Area of Science:
- Nephrology
- Mitochondrial Biology
- Medical Imaging
Background:
- Mitochondrial dysfunction is key in acute kidney injury (AKI) pathogenesis.
- In vivo imaging of kidney mitochondria remains challenging.
- Previous studies utilized ex vivo kidney tissue, but in vivo methods are needed.
Purpose of the Study:
- To develop and validate in vivo multiphoton microscopy for imaging kidney mitochondrial structure and function in rodents.
- To investigate mitochondrial responses to ischemia-reperfusion injury and drug-induced toxicity in real-time.
Main Methods:
- Utilized multiphoton microscopy with endogenous and exogenous fluorophores in anesthetized rodents.
- Imaged mitochondrial nicotinamide adenine dinucleotide (NAD+) levels and mitochondrial membrane potential using TMRM dye.
- Assessed mitochondrial structure (shape, fragmentation) in proximal and distal tubules.
Main Results:
- In vivo imaging successfully captured kidney mitochondrial structure and function.
- Ischemia caused increased mitochondrial NAD+ and rapid membrane potential dissipation in proximal tubules.
- Proximal tubules showed mitochondrial fragmentation, while distal tubules were better preserved.
- Gentamicin exposure induced mitochondrial changes in proximal tubules, but not distal tubules.
Conclusions:
- Multiphoton microscopy enables real-time in vivo visualization of kidney mitochondrial dynamics.
- Proximal tubules are more vulnerable to ischemia-reperfusion and gentamicin toxicity than distal tubules.
- This technique offers a powerful tool for studying AKI pathogenesis and evaluating potential therapeutics.
Related Concept Videos
01:30Acute Kidney Injury IV: Diagnostic Studies and Prevention
01:29Acute Kidney Injury II: Pathophysiology
01:22Acute Kidney Injury I: Introduction