Introduction:Fibronectin is a dimeric glycoprotein found in the extracellular matrix of most tissues. It can influence cell growth, adhesion and migration. Fibronectin synthesis is overexpressed in hypertension. However, the respective effects of humoral factors, including angiotensin II, and mechanical factors in vascular remodelling have not yet been clarified. To study fibronectinde novosynthesis in the arterial wall, we have developed a new model for organ culture of rabbit thoracic aorta.Methods:Arteries held at theirin vivolength were incubated and perfused (40ml/min) in DME medium containing antibiotics, supplemented widt 20% fetal calf serum or 5% bovine serum albumin. In a series of experiments, angiotensin II (10-6mol/l) and indomethacin (10-5mol/l) were added to culture media. Vessels were pressurized at 0, 80 or 150 mmHg, and incubated for 3 days at 37±C under 5% CO2.De novosynthesis of fibronectin was detected by immunofluorescence using anti-cellular fibronectin antibodies (1:200).Results:In the absence of angiotensin II and serum, fibronectin was expressed in the sub-endothelium at 80 mmHg, and in the inner media at 150 mmHg. In the presence of serum, fibronectin expression was increased by the high pressure. When angiotensin II was added, a gradient of fibronectin became apparent in the inner media at 80 mmHg with a marked expression at the luminal side. Angiotensin II markedly enhanced fibronectin expression at 150 mmHg, the protein being detected in almost all of the media.Conclusion: Our results indicate that both angiotensin II and transmural pressure can induce fibronectin expression in the arterial wall, and the two act synergically.