Related Experiment Videos
Disparities in the respiratory burst between human and rat neutrophils
J L Johnson1, E E Moore, A A Hiester
1University of Colorado Health Sciences Center Department of Surgery, Denver Health Medical Center, USA.
Abstract:
The importance of reactive oxygen species (ROS) in neutrophil (PMN)-mediated injury to host tissues has been strongly implicated in a number of animal models. Peculiarities of the laboratory rat PMN, including an apparent paucity of superoxide release, prompted us to examine disparities in the respiratory burst between human and rat PMNs. Using isolated PMNs, we examined oxygen consumption, superoxide release, nitrate/nitrite release, and dihydrorhodamine (DHR) oxidation in response to an array of soluble stimuli. Our findings confirm that intact rat PMNs release little superoxide in comparison to human PMNs when primed and activated by soluble stimuli. For example, PMA-activated human PMNs released superoxide at 10.1 +/- 2.7 times the rate of rat PMNs (P < 0.01). However, measurements of oxygen consumption, cell-associated oxidant production (by DHR oxidation) and release of superoxide from electroporated cells suggests that rat PMNs generate oxidants at rates equivalent to human PMNs but preferentially release them in an intracellular compartment. Implications for the study of PMN-mediated oxidant injury in animal models are discussed.
Insights
Rat neutrophils generate oxidants similarly to human neutrophils but release less superoxide extracellularly. This finding impacts the interpretation of neutrophil-mediated oxidant injury in animal models.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Neutrophils (PMNs) are crucial in host defense but can cause tissue injury via reactive oxygen species (ROS).
- Animal models are vital for studying PMN-mediated injury, yet species-specific differences in PMN function may affect model validity.
- Previous observations suggested lower superoxide release from rat PMNs compared to human PMNs.
Purpose of the Study:
- To investigate disparities in the respiratory burst between human and rat neutrophils.
- To determine if differences in superoxide release reflect overall oxidant generation or compartmentalization.
- To assess the implications for using rat models to study PMN-mediated oxidant injury.
Main Methods:
- Isolated human and rat neutrophils were stimulated with various agents.
- Measurements included oxygen consumption, extracellular superoxide release, and nitrate/nitrite release.
- Dihydrorhodamine (DHR) oxidation assessed cell-associated oxidant production, and superoxide release from electroporated cells was measured.
Main Results:
- Intact rat PMNs released significantly less superoxide than human PMNs upon stimulation (e.g., PMA activation: rat vs. human ratio of 1:10.1).
- However, rat PMNs exhibited comparable oxygen consumption and cell-associated oxidant production (DHR oxidation) to human PMNs.
- Electroporation studies indicated that rat PMNs generate oxidants at rates similar to human PMNs but retain them intracellularly.
Conclusions:
- Rat neutrophils generate oxidants at rates comparable to human neutrophils.
- The lower extracellular superoxide release from rat PMNs is due to preferential intracellular retention.
- These findings necessitate careful consideration when extrapolating results from rat models of PMN-mediated oxidant injury to human conditions.