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Sulfite-mediated oxidative stress in kidney cells
Annette S Vincent1, Beng Gek Lim, Jasmine Tan
1Department of Biochemistry, Faculty of Medicine, National University of Singapore, Singapore.
Kidney International
|January 14, 2004
Summary
Sulfite exposure increases reactive oxygen species (ROS) and depletes ATP in kidney cells by inhibiting glutamate dehydrogenase. This study investigates sulfite
Area of Science:
- Biochemistry
- Cell Biology
- Nephrology
Background:
- Chronic kidney disease is linked to oxidative stress.
- Elevated serum sulfite and related compounds are observed in hemodialysis patients.
- Metabisulfite administration can induce kidney cell damage.
Purpose of the Study:
- To investigate the effects of sulfite on kidney cells.
- To determine the impact of sulfite on mitochondrial function and ATP production.
- To explore the mechanisms underlying sulfite-induced kidney cell injury.
Main Methods:
- Measurement of reactive oxygen species (ROS) using dichlorofluorescein fluorescence.
- Assessment of intracellular ATP levels via the luciferin-luciferase reaction.
- Polarographic monitoring of sulfite oxidation in isolated kidney mitochondria.
- Assay of glutamate and malate dehydrogenase activities.
- Determination of cell viability using the MTT assay.
Main Results:
- Sulfite exposure (5-500 micromol/L) caused an immediate increase in ROS in kidney cell lines (MDCK, OK).
- Intracellular ATP levels were depleted, linked to inhibition of mitochondrial glutamate dehydrogenase by sulfite.
- Sulfite inhibited ATP biosynthesis from glutamate oxidation in rat kidney mitochondria.
- Mitochondrial membrane potential and cell viability remained unaffected.
Conclusions:
- Micromolar sulfite induces ROS and ATP depletion in kidney cells.
- Inhibition of mitochondrial glutamate dehydrogenase by sulfite contributes to ATP depletion.
- While malate dehydrogenase is also inhibited, its high levels in kidney mitochondria may offer a buffer.