Granulocytosis and increased adhesion molecules after resistive loading of the diaphragm.
Upregulation of endothelial cell adhesion molecules, followed by an influx of granulocytes and macrophages, can contribute to exertion-induced skeletal muscle injury. The purpose of this study was to quantify circulating leukocyte subsets, diaphragm injury and infiltrating leukocyte subsets, and surface expression of vascular cell adhesion molecule (VCAM)-1 and intracellular adhesion molecule (ICAM)-1 in the diaphragm after inspiratory resistive loading (IRL). Eight New Zealand white rabbits underwent 1.5 h of IRL and seven control rabbits underwent a sham procedure. Blood samples, taken at baseline and 2, 6, 12, 24, 48 and 72 h after the onset of IRL or sham, showed that band cell counts had increased at 6 h post-IRL. Point counting of haematoxylin and eosin-stained cross-sections, sampled at 72 h post-IRL, showed greater injury in diaphragms from IRL rabbits compared with controls. Immunohistochemical processing showed increased expression of ICAM-1 and VCAM-1, and higher granulocyte and macrophage counts in IRL diaphragms than control diaphragms. Macrophages were the predominant inflammatory cells. Increased intracellular adhesion molecule-1 and vascular cell adhesion molecule-1 expression, and infiltration of granulocytes and macrophages may contribute to inspiratory resistive loading-induced diaphragm injury.
Wang
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School of Rehabilitation Sciences, T325-2211 Wesbrook Mall, Vancouver, BC Canada V6T 2B5.
Jiang
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Road
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Redenbach
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Reid
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WD
D000403:Airway Resistance / Q000276:immunology*; D000818:Animals; D015815:Cell Adhesion Molecules / Q000276:immunology*; D003964:Diaphragm / Q000293:injuries* / Q000473:pathology / Q000503:physiopathology*; D006098:Granulocytes / Q000276:immunology* / Q000473:pathology*; D007958:Leukocyte Count; D005082:Physical Exertion; D011817:Rabbits; D014939:Work of Breathing / Q000276:immunology
D015815:Cell Adhesion Molecules