Related Experiment Video
Updated: Jul 5, 2026
06:20
Live-imaging of Mitochondrial System in Cultured Astrocytes
Published on: November 16, 2021
Mitochondrial swelling measurement in situ by optimized spatial filtering: astrocyte-neuron differences
Akos A Gerencser1, Judit Doczi, Beata Töröcsik
1Department of Medical Biochemistry, Semmelweis University, Neurobiochemical Group, Hungarian Academy of Sciences, Szentagothai Knowledge Center, Budapest, Hungary.
Biophysical Journal
|April 22, 2008
Summary
We developed a new microscopy assay to measure mitochondrial swelling, a key sign of cell damage. This sensitive technique, the "thinness ratio," accurately detects swelling in astrocytes but not neurons.
Area of Science:
- Cell Biology
- Mitochondrial Biology
- Microscopy and Imaging
Background:
- Mitochondrial swelling is a critical indicator of mitochondrial dysfunction and the opening of the mitochondrial permeability transition pore.
- Existing methods for assessing mitochondrial swelling are often limited in scope or sensitivity.
Purpose of the Study:
- To introduce and validate a novel, quantitative in situ single-cell assay for measuring mitochondrial swelling using standard fluorescence microscopy.
- To develop a robust and sensitive technique for assessing mitochondrial dynamics and health at the cellular level.
Main Methods:
- Developed a morphometric technique quantifying mitochondrial diameter using targeted fluorescent proteins.
- Applied spatial bandpass filtering to fluorescence micrographs, analyzing the ratio of high- to low-frequency filtered intensities (the 'thinness ratio').
- Validated the 'thinness ratio' technique through image formation modeling and experiments in cultured cortical neurons and astrocytes.
Main Results:
- The 'thinness ratio' assay demonstrated high sensitivity to mitochondrial swelling, independent of mitochondrial fission or fusion.
- Frequency domain image processing provided robustness and subresolution sensitivity, surpassing traditional shape measurement limitations.
- In situ astrocytic mitochondria exhibited swelling upon short-term uncoupling or oxidative phosphorylation inhibition, a response not observed in cultured cortical neurons.
Conclusions:
- The 'thinness ratio' is a novel, sensitive, and robust method for quantifying mitochondrial swelling in situ.
- This assay reveals differential responses of astrocyte and neuron mitochondria to metabolic stress, highlighting cell-type-specific mitochondrial dynamics.
