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Alterations of the endothelial function of isolated aortae in rats with adjuvant arthritis
Z Y Fang1, J Fontaine, P Unger
1Cardiology Department, Erasmus Hospital, Brussels, Belgium.
Abstract:
Adjuvant arthritis was induced in 30 male Wistar rats by injection into the tail of heat-killed Mycobacterium butyricum. Three weeks later, 14 of these rats exhibited severe arthritic lesions. Their thoracic aortae were studied in parallel with those isolated from a control group. On rings precontracted with phenylephrine (0.1 microM), the endothelium-dependent relaxations produced by acetylcholine and histamine were significantly diminished in the arthritic group as compared to the control group. Moreover, the increase in tone induced by incubation with methylene blue (10 microM) (a nonspecific inhibitor of endothelium-derived relaxing factor) was significantly less pronounced in preparations isolated from the arthritic group. On the other hand, relaxations produced by the endothelium-independent vasodilators verapamil and nitroprusside were similar in both groups. It is concluded that adjuvant arthritis modifies the endothelium-derived relaxing factor-mediated responses of rat aorta.
Insights
Adjuvant arthritis in rats impairs endothelium-dependent aortic relaxations, indicating altered nitric oxide pathway function. This study reveals significant vascular dysfunction in this arthritis model.
Area of Science:
- Cardiovascular Research
- Immunology
- Pharmacology
Background:
- Adjuvant arthritis is an experimental model used to study inflammatory conditions.
- Vascular endothelial function plays a crucial role in cardiovascular health.
- Arthritis can lead to systemic complications, including cardiovascular changes.
Purpose of the Study:
- To investigate the impact of adjuvant arthritis on the endothelium-dependent relaxations of rat thoracic aorta.
- To assess the role of endothelium-derived relaxing factor (EDRF) in vascular responses during adjuvant arthritis.
Main Methods:
- Adjuvant arthritis was induced in male Wistar rats using Mycobacterium butyricum.
- Thoracic aortic rings from arthritic and control rats were precontracted with phenylephrine.
- Endothelium-dependent relaxations to acetylcholine and histamine, and endothelium-independent relaxations to verapamil and nitroprusside were measured.
Main Results:
- Endothelium-dependent relaxations to acetylcholine and histamine were significantly diminished in arthritic rats.
- The response to methylene blue, an inhibitor of endothelium-derived relaxing factor, was less pronounced in arthritic aortae.
- Endothelium-independent relaxations to verapamil and nitroprusside were similar between groups.
Conclusions:
- Adjuvant arthritis significantly alters endothelium-derived relaxing factor-mediated responses in rat aorta.
- The findings suggest impaired nitric oxide pathway function in the vascular system of rats with adjuvant arthritis.
- This study highlights potential cardiovascular implications of inflammatory conditions like adjuvant arthritis.