Objective To explore the antithrombotic effect of recombinant hirudin in rats. Method We randomized 160 SD rats into eight
groups, twenty rats in each group. Group 1, 2, 3 and 4 received rH 1.000, 0.500, 0.250, 0.125 mg·kg -1 ; group 5 received refludan 0.500 mg·kg -1 ; group 6 received heparin 2 000 U·kg -1 ; the model group receive the same volume of sodium chloride injection, i.v., and the control group received nothing. After 10 min, filter paper marinated in 50% FeCl 3 solution was attached to the low front part of the coronary artery for 60 min in group 1, 2, 3, 4, 5, 6 and in the model group to induce
thrombosis. The control group were operated in the same way but had no FeCl 3. The antithrombosis effect of rH was evaluated by scores of infarcted area, Evans Blue content of left ventricle myocardium, difference of SOD activity and MDA content. Results The scores of infarcted area in group 1, 2, 3, 4 and 5 were respectively 12,16,24,28,19, which were all
significantly lowered than 39 in the model group. Evans Blue content in group 1, 2, 3, 5 and 6 was significantly lowered than in control group (P<0.01). The SOD activity of myocardium in group 1 was(54.64±12.05) NU·mg -1 , significantly higher than(30.46±8.73) NU·mg -1 in the model group (P<0.01).The SOD activity of myocardium in group 2, 3 and 6 was also significantly higher than in the model group (P<0.05). The MDA content in group 1, 2, 3, 5 and 6 was significantly lowered than in the model group (P<0.01). Coronary artery thrombosis was showed in group 3, 4 by pathological examination. Coronary artery thrombosis in group 2 was obviously reduced. Conclusion rH has an antithrombotic effect which is dose-dependent.