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- Title
Bradykinin- and sodium nitroprusside-induced increases in capillary tube haematocrit in mouse cremaster muscle are associated with impaired glycocalyx barrier properties.
- Authors
VanTeeffelen, Jurgen W. G. E.; Constantinescu, Alina A.; Brands, Judith; Spaan, Jos A. E.; Vink, Hans
- Abstract
Previous studies have suggested that agonists may increase functionally perfused capillary volume by modulation of blood-excluding glycocalyx volume, but direct evidence for this association is lacking at the moment. Using intravital microscopic visualization of mouse cremaster muscle, we determined the effects of bradykinin (10−5m) and sodium nitroprusside (10−6m) on capillary tube haematocrit and glycocalyx barrier properties. In control C57Bl/6 mice ( n= 10), tube haematocrit in capillaries ( n= 71) increased ( P < 0.05) from 8.7 ± 0.3% during baseline to 21.2 ± 1.2 and 22.2 ± 0.9% during superfusion with bradykinin and nitroprusside, respectively. In parallel, the exclusion zone of FITC-labelled 70 kDa dextrans decreased ( P < 0.05) from 0.37 ± 0.01 μm during baseline to 0.17 ± 0.01 μm with bradykinin and 0.15 ± 0.01 μm with nitroprusside. Bradykinin and nitroprusside had no effect on dextran exclusion and tube haematocrit in capillaries ( n= 55) of hyperlipidemic ApoE3-Leiden mice, which showed impaired exclusion of 70 kDa dextrans (0.05 ± 0.02 μm; P < 0.05 versus C57Bl/6) and increased capillary tube haematocrit (23 ± 0.8%; P < 0.05 versus C57Bl/6) under baseline conditions, indicating glycocalyx degradation. Our data show that vasodilator substances increase functionally perfused capillary volume and that this effect is associated with a reduction in glycocalyx exclusion of 70 kDa dextrans. Modulation of glycocalyx volume might represent a novel mechanism of perfusion control at the capillary level.
- Publication
Journal of Physiology, 2008, Vol 586, Issue 13, p3207
- ISSN
0022-3751
- Publication type
Article
- DOI
10.1113/jphysiol.2008.152975