Related Experiment Video
Updated: Jul 8, 2026
Imaging Neutrophil Migration in the Mouse Skin to Investigate Subcellular Membrane Remodeling Under Physiological Conditions
Published on: May 10, 2022
Dynamics of neutrophil infiltration during cutaneous wound healing and infection using fluorescence imaging
Min-Ho Kim1, Wei Liu, Dori L Borjesson
1Department of Biomedical Engineering, University of California at Davis, Davis, California 95616, USA.
Abstract:
Neutrophil influx is an early inflammatory response that is essential for the clearance of bacteria and cellular debris during cutaneous wounding. A non-invasive real-time fluorescence imaging technique was developed to examine the kinetics of enhanced green fluorescence protein-polymorphonuclear leukocyte (EGFP-PMN) influx within a wound. We hypothesized that infection or systemic availability would directly regulate the dynamics of EGFP-PMN recruitment and the efficiency of wound closure. Neutrophil recruitment increased dramatically over the first 24 hours from 10(6) at 4 hours up to a maximum of 5 x 10(6) EGFP-PMNs at 18 hours. A high rate of EGFP-PMN turnover was evidenced by approximately 80% decrease in EGFP signal within 6 hours. In response to wound colonization by Staphylococcus aureus or injection of GM-CSF, systemic PMNs increased twofold above saline control. This correlated with an increase in EGFP-PMN recruitment up to approximately 10(7) within the wound. Despite this effect by these distinct inflammatory drivers, wound closure occurred at a rate similar to the saline-treated control group. In summary, a non-invasive fluorescence-based imaging approach combined with genetic labeling of neutrophils provides a dynamic inner view of inflammation and the kinetics of neutrophil infiltration into the wounded skin over extended durations.
Insights
Neutrophil influx into wounds is crucial for healing. This study used real-time imaging to track enhanced green fluorescence protein-polymorphonuclear leukocytes (EGFP-PMNs), revealing how infection and growth factors impact their recruitment and wound closure.
Area of Science:
- Wound healing research
- Inflammation and immunology
- Biomedical imaging techniques
Background:
- Neutrophil influx is a critical early inflammatory response in cutaneous wound healing.
- Efficient clearance of bacteria and debris by neutrophils is essential for proper wound repair.
- Understanding neutrophil dynamics is key to optimizing wound healing outcomes.
Purpose of the Study:
- To develop a non-invasive real-time fluorescence imaging technique for examining neutrophil kinetics in wounds.
- To investigate the hypothesis that infection or systemic factors regulate neutrophil recruitment and wound closure efficiency.
- To quantify neutrophil influx and turnover rates during the wound healing process.
Main Methods:
- Development of a non-invasive real-time fluorescence imaging technique.
- Utilized enhanced green fluorescence protein-polymorphonuclear leukocytes (EGFP-PMNs) to track neutrophil migration.
- Induced wound colonization with Staphylococcus aureus or administered GM-CSF to modulate systemic inflammation.
- Monitored EGFP-PMN influx, turnover, and wound closure rates over time.
Main Results:
- Neutrophil recruitment peaked at approximately 5 x 10^6 EGFP-PMNs at 18 hours post-wounding.
- A rapid EGFP-PMN turnover was observed, with an 80% signal decrease within 6 hours.
- Wound colonization or GM-CSF administration doubled systemic PMNs and increased wound EGFP-PMN recruitment up to 10^7.
- Despite increased neutrophil influx, wound closure rates remained similar to controls.
Conclusions:
- Non-invasive fluorescence imaging provides dynamic insights into neutrophil infiltration during wound healing.
- While infection and systemic factors increase neutrophil recruitment, they do not accelerate wound closure in this model.
- The developed imaging approach offers a valuable tool for studying inflammatory responses in vivo.
