Related Experiment Videos
Superoxide production by stimulated neutrophils: temperature effect
1Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.
Free Radical Research Communications
|January 1, 1991
Summary
Neutrophil activation produces superoxide, but high temperatures (37°C) limit its duration. Lowering temperatures (25°C) allows prolonged superoxide generation, suggesting neutrophils can produce radicals for extended periods in vivo.
Area of Science:
- Immunology
- Cellular Biology
- Biochemistry
Background:
- Neutrophil activation generates superoxide and other oxygen-derived species crucial for microbial killing.
- Previous studies suggest neutrophil oxidative burst is a short-lived event, peaking within minutes at 37°C.
- Conflicting findings exist regarding the duration of superoxide production by stimulated neutrophils in vitro.
Purpose of the Study:
- To investigate the effect of temperature on the kinetics of radical generation by neutrophils stimulated with phorbol 12-myristate 13-acetate (PMA).
- To reconcile conflicting data on the duration of neutrophil superoxide production.
- To understand the prolonged capacity for oxy-radical generation by neutrophils.
Main Methods:
- Utilized electron paramagnetic resonance (EPR) spectroscopy with spin-trapping.
- Employed SOD-inhibitable ferricytochrome c reduction assay to monitor superoxide production.
- Stimulated neutrophils at 25°C and 37°C in RPMI 1640 medium and Hank's balanced salt solution (HBSS) with continuous oxygen supply.
Main Results:
- Neutrophils stimulated at 25°C generated superoxide continuously for several hours.
- At 37°C, particularly in HBSS, superoxide production decreased rapidly.
- Cessation of superoxide generation at 37°C was reversible upon lowering the temperature to 25°C.
Conclusions:
- Neutrophil oxy-radical generation is temperature-dependent, with lower temperatures supporting prolonged production.
- The findings suggest neutrophils may generate oxy-radicals for extended periods in vivo.
- This study helps explain the transient nature of neutrophil radical formation observed in some in vitro experiments and challenges the perception of it being ephemeral.