Ambient particulate matter induces relaxation of rat aortic rings in vitro.

A.M. Knaapen*, G.J.M. den Hartog, A. Bast, P.J.A. Borm

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

19 Citations (Web of Science)


Hum Exp Toxicol 2001 May;20(5):259-65 Related Articles, Books, LinkOut

Ambient particulate matter induces relaxation of rat aortic rings in vitro.

Knaapen AM, den Hartog GJ, Bast A, Borm PJ.

Department of Fibre and Particle Toxicology, Medical Institute of Environmental Hygiene, Dusseldorf, Germany.

Epidemiological studies have shown an association between ambient levels of particulate matter (PM) and increased mortality from cardiovascular diseases. However, the underlying mechanisms are still not clear. We hypothesised that PM, when translocated after inhalation, could affect vascular smooth muscle function. Therefore, total suspended particulate matter (TSP) was sampled and investigated for its ability to affect aortic muscle contraction. Both TSP and TSP supernatant (TSP-sup) induced a concentration-dependent relaxation of phenylephrine (PE)-precontracted aortic rings. Relaxation induced by 100 microg/ml TSP was 51.5 +/- 3.1% of total contraction. At 60 and 100 microg/ml, relaxation induced by TSP was significantly higher compared to TSP-sup. Ultrafine TiO2, used as a model to investigate the role of ultrafine particles, did not show an effect. Soluble iron, present in TSP suspensions, seems not to be involved, as chelating with deferoxamine did not affect TSP-induced relaxation. However, TSP effects were inhibited by Trolox, suggesting a role of oxidants. Nudation of aortic rings showed that effects of TSP were only partly endothelium-dependent, while preincubation with L-NAME increased TSP-induced relaxation. From these data, we conclude that both the particle core and soluble components of TSP can affect the smooth muscle function, leading to changes in the vascular contractile response.

Original languageEnglish
Pages (from-to)259-265
Number of pages7
JournalHuman & Experimental Toxicology
Issue number5
Publication statusPublished - 1 Jan 2001

Cite this