title: Dynamics of neutrophil infiltration during cutaneous wound healing and infection using fluorescence imaging.
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.
authors.affiliation: Department of Biomedical Engineering, University of California at Davis, Davis, California 95616, USA.
authors.forename: Min-Ho
authors.initials: MH
authors.lastname: Kim
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Dori L
authors.initials: DL
authors.lastname: Borjesson
authors.forename: Fitz-Roy E
authors.initials: FR
authors.lastname: Curry
authors.forename: Lloyd S
authors.initials: LS
authors.lastname: Miller
authors.forename: Ambrose L
authors.initials: AL
authors.lastname: Cheung
authors.forename: Fu-Tong
authors.initials: FT
authors.lastname: Liu
authors.forename: R Rivkah
authors.initials: RR
authors.lastname: Isseroff
authors.forename: Scott I
authors.initials: SI
authors.lastname: Simon
mesh_terms: D000818:Animals; D005260:Female; D005453:Fluorescence; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D020556:Neutrophil Infiltration; D012867:Skin / Q000473:pathology*; D013207:Staphylococcal Skin Infections / Q000276:immunology*; D014945:Wound Healing / Q000276:immunology*
chemical_list: D016178:Granulocyte-Macrophage Colony-Stimulating Factor