Experimental bacterial pneumonia in rabbits: polymorphonuclear leukocyte margination and sequestration in rabbit lungs and quantitation and kinetics of /sup 51/Cr-labeled polymorphonuclear leukocytes in E. coli-induced lung lesions
A relationship between the circulating and marginal polymorphonuclear leukocyte (PMN) pools was documented using /sup 51/Cr-labeled leukocytes as a marker. /sup 51/Cr-leukocytes marginating in the lungs were found to decrease following a first-order exponential decline, while /sup 51/Cr radioactivity accumulated in the liver and the spleen. Intravenously administered endotoxin caused a rapid selective disappearance of PMNs from the circulation. The percentage of infused /sup 51/Cr cells disappearing was equal to the percentage of disappearance of host cells. The PMNs were found to sequester in the lungs, with peak sequestration of labeled cells occurring 5 min after an endotoxin challenge. Over the next 25 min the /sup 51/Cr radioactivity in the lungs declined. Large numbers of PMNs, probably newly derived from the bone marrow, were observed histologically to be sequestered in the lung vasculature 90 min after an endotoxin dose, while the early sequestration of circulating leukocytes could not be assessed histologically. Pulmonary inflammatory lesions were induced selectively with Escherichia coli in the left lower lobes of rabbits, leaving the right lower lobes as intrinsic controls. PMN-accumulation into the lesions was quantitated using /sup 51/Cr-labeled blood leukocytes. With the aid of /sup 125/I-labeled E. coli, a logarithmic dose-response relationship was found between the number of E. coli and of PMNs. Over a 6-hr period circulating PMNs were found to accumulate in a lesion in the left lower lobe, whereas in the control right lower lobe, leukocyte radioactivity declined. These findings were confirmed with the aid of lavages of the right and left lungs. Two peaks of PMN-accumulation were found by studying leukocyte kinetics: a larger peak between 0 and 6 hr and a smaller peak 18-24 hr after instillation of the microorganisms. Histologic studies confirmed the accumulation of leukocytes, and by 3 weeks showed a complete resolution of the lesions.
- Research Organization:
- Department of Pathology, University of Toronto, Ontario, Canada
- OSTI ID:
- 5742591
- Journal Information:
- Exp. Lung Res.; (United States), Journal Name: Exp. Lung Res.; (United States) Vol. 4:1; ISSN EXLRD
- Country of Publication:
- United States
- Language:
- English
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551001 -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
BACTERIA
BETA DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BIOLOGICAL MODELS
BLOOD
BLOOD CELLS
BODY
BODY FLUIDS
CHROMIUM 51
CHROMIUM ISOTOPES
DAYS LIVING RADIOISOTOPES
DISEASES
ELECTRON CAPTURE RADIOISOTOPES
ESCHERICHIA COLI
EVEN-ODD NUCLEI
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
LEUKOCYTES
LUNGS
MAMMALS
MATERIALS
MICROORGANISMS
NUCLEI
ODD-EVEN NUCLEI
ORGANS
PNEUMONIA
RABBITS
RADIOISOTOPES
RESPIRATORY SYSTEM
RESPIRATORY SYSTEM DISEASES
TRACER TECHNIQUES
UPTAKE
VERTEBRATES