Burn-activated neutrophils and tumor necrosis factor-alpha alter endothelial cell actin cytoskeleton and enhance monolayer permeability.
BACKGROUND
This study examined the hypothesis that exposure of an endothelial cell (EC) monolayer to tumor necrosis factor-alpha (TNF-alpha) and that burn-activated neutrophils alter EC actin cytoskeleton and enhance the permeability of the monolayer.


METHODS
Neutrophils were harvested from rats that had undergone a 45% surface area burn (BURN-neutrophil) or uninjured control rats. ECs were grown on polyester filters or fibronectin-coated glass slides and exposed for 4 hours to media, TNF-alpha (100 ng/mL), or TNF-alpha plus BURN-neutrophil or uninjured control rats (10(7) cells). Monolayer permeability was assessed by measuring the flux of albumin across the cells. EC surface area and microfilament number and length were determined by the staining of actin microfilaments with rhodamine phalloidin followed by fluorescent microscopy.


RESULTS
The amount of albumin that moved across the monolayer in response to TNF-alpha plus BURN-neutrophil was twice that of media alone (P <.05) or TNF-alpha alone (P <.05). The number and length of actin microfilaments in ECs exposed to TNF-alpha plus BURN-neutrophil were significantly less than that of cells exposed to media alone or TNF-alpha alone.


CONCLUSIONS
These data are consistent with a hypothesis that TNF-alpha plus BURN-neutrophil affect endothelial monolayer permeability by altering EC actin cytoskeletal organization.
Departments of Surgery and Physiology, University of Texas Southwestern Medical School and the Dallas Veterans Affairs Medical Center, 75235, USA.
K
K
Wright
F
F
Nwariaku
N
N
Halaihel
C
C
Schulman
H L
HL
Yin
R H
RH
Turnage
D000199:Actins / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D002056:Burns / Q000097:blood* / Q000503:physiopathology; D002463:Cell Membrane Permeability / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000187:drug effects / Q000502:physiology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D018375:Neutrophil Activation; D009504:Neutrophils / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D014471:Umbilical Veins
D000199:Actins; D014409:Tumor Necrosis Factor-alpha