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Monitoring Astrocyte Reactivity and Proliferation in Vitro Under Ischemic-Like Conditions
Published on: October 21, 2017
Extracellular superoxide dismutase in cultured astrocytes: decrease in cell-surface activity and increase in medium
Ichiro Iitsuka1, Akiko Motoyoshi-Yamashiro, Mitsuaki Moriyama
1Laboratory of Integrative Physiology in Veterinary Science, Osaka Prefecture University, Rinku-ourai Kita 1-58, Izumisano, Osaka 598-8531, Japan.
Neurochemical Research
|June 29, 2012
Summary
Extracellular superoxide dismutase (EC-SOD) in astrocytes helps detoxify harmful superoxide anion (O(2)(-)) in the brain. Its regulation in astrocytes may be crucial for defense against oxidative stress.
Area of Science:
- Neuroscience
- Biochemistry
- Cell Biology
Background:
- Pathological conditions like ischemia/reperfusion generate significant superoxide anion (O(2)(-)) in the brain.
- Extracellular superoxide dismutase (EC-SOD) is crucial for detoxifying O(2)(-) in the extracellular space, but its role in the brain is poorly understood.
- Understanding EC-SOD's function in brain extracellular space is vital for addressing oxidative stress.
Purpose of the Study:
- To directly measure cell-surface superoxide dismutase (SOD) activity in primary cultured rat brain cells.
- To investigate the expression and regulation of EC-SOD in different brain cell types, particularly astrocytes.
- To evaluate the role of astrocyte EC-SOD in brain defense mechanisms against oxidative stress.
Main Methods:
- Measurement of cell-surface SOD activity using inhibition of color development by xanthine oxidase/hypoxanthine.
- Detection and semi-quantitative analysis of SOD isozyme mRNA levels (including EC-SOD) via RT-PCR in cultured neurons, microglia, and astrocytes.
- Stimulation of astrocytes with lipopolysaccharide (LPS) to assess changes in cell-surface and medium SOD activity.
Main Results:
- Astrocyte cell-surface SOD activity was measurable, unlike in neurons and microglia.
- Astrocytes exhibited significantly higher EC-SOD mRNA levels compared to neurons and microglia.
- LPS stimulation decreased astrocyte cell-surface SOD activity while increasing SOD activity in the medium, suggesting EC-SOD release.
Conclusions:
- Astrocyte-derived EC-SOD plays a significant role in detoxifying extracellular O(2)(-) in the brain.
- The regulation of EC-SOD in astrocytes, potentially through release mechanisms, contributes to the brain's defense against oxidative stress.
- These findings highlight astrocytes and EC-SOD as key components in managing brain oxidative damage.
