Dg. Moon et al., FIBRONECTIN INHIBITION OF PLATELET THROMBUS FORMATION IN AN IN-VIVO PORCINE MODEL OF VASCULAR INJURY, Thrombosis research, 76(4), 1994, pp. 343-351
Platelets adhere and aggregate in response to exposed subendothelial m
atrix during vascular injury. The present study examines the effect of
plasma fibronectin on platelet deposition at a site of vascular injur
y in an in vivo porcine model. The internal carotid arteries in anesth
etized Yorkshire pigs were bilaterally exposed and the distal half of
each vessel stripped of endothelium. Following stripping, one in situ
carotid artery preparation was filled with 0.5 mg/ml porcine plasma fi
bronectin and the other artery filled with vehicle solution, to serve
as a control. After five minutes, 6-7 x 10(8) (111)lndium-labeled auto
logous platelets were infused via a femoral vein cannula, and carotid
blood flow was re-established for 20 minutes. The vessel segments were
excised and deposition of platelets determined. Vascular stripping in
creased platelet deposition 52-fold, as compared to unstripped vessel
segments. Fibronectin pretreatment did not affect platelet deposition
in control vessel segments but decreased platelet deposition by 77% in
stripped vessel segments. Transmission and scanning electron microsco
py indicated that reduced platelet deposition in the fibronectin treat
ed group was due to decreased platelet aggregation rather than decreas
ed adhesion.