To investigate the effects of propyl gallate (PrG) on the thrombus formation time and the coagulation/fibrinolysis system in an experimental carotid artery thrombosis model in rats. Fifty SD rats were randomly divided into 5 groups (10 animals/group): the normal group (normal saline 2 mL/kg)

the model group (normal saline

2 mL/kg)

the heparin control group (1 250 IU/kg)

the low dose PrG group (30 mg/kg)

and the high dose PrG group (60 mg/kg). Thirty minutes after intravenous injection of saline or the corresponding drugs

a carotid artery thrombus was induced by continuous electric stimulation in all rats except for those in the normal group. The duration from the initiation of the electric stimulation to the sudden drop in carotid temperature was recorded as the thrombus formation time. Levels of plasma tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) were determined by ELISA. PrG (30 and 60 mg/kg) can prolong the thrombus formation time

but the effect was obviously weaker than that of heparin (P<0.05

P<0.01). Compared with the model group

PrG (30 and 60 mg/kg) elevated the plasma activity of t-PA (both P<0.05) and showed an increasing tendency in elevating the ratio of t-PA/PAI-1 (P>0.05)

while it had no significant effect on the level of PAI-1. PrG has a certain antithrombotic effect and can slightly regulate the imbalance of the t-PA /PAI-1 ratio.