| Objective:To investigate the effect of hirudin which was applied locally to the vein congestion on skin flap through the rabbit ear model. Methods: 18 ordinary rabbits, male and female informaly, body weight (2200±200g), were randomly divided into three groups:a control group (group A:injecting saline group) and two treatment group (group B:Low molecular heparin, Group C:recombinant hirudin group), each of 6. stoping feeding before experiments, intravenous injection Anesthesia was performed by 2% pentobarbital sodium with 0.2 mg/kg body weight. The animal was then placed on the operating room table in a lateral recumbent position. using sterile technique, an anxial-pattern skin lap precisely 3 cm wide and 6 cm long was elevated in a plane directly above the perichondrium on the dorsum of the ear, A 1cm skin pedicle was left at the base of the flap, which contained the central auricular nerve, artery, and vein. Under loupe magnification, the central auricular vein and nerve were ligated and divided at the base of the flap. In addition, all other collateral vessels were ligated and divided, leaving the central auricular artery as the sole blood supply to the flap and the 1cm skin pedicle as the only means of venous return. The treatment group were given immediately hirudin (1u/1ml/flap) or low-molecular-weight heparin (0.5 mg/1ml/flap), the control group saline (lml/flap), sutured by 5-0 silk. Loss of hair, hematoma formation, the flap survival were observed, capillary thrombosis and neutrophil aggregation and the amountof the flap were observed through histology, TXB2 protein content by enzyme linked immunosorbent assay.Results:1 Macroscopic observation show that all the skin flop has swelling obviously,on the first day all of the skin flap.On the third day ,compare to the group B and C the congestion of the flap in group A has obviously aggravation.on the seven day,the congestion of the flap in group B and C has disappeared.And the flap of the group A has necrosis.2 The survial rate of the flap:Low-molecular-weight heparin and recombinant hirudin treatment group respectively (92.33±1.67)% and (94.83±1.91%), higer than those in the saline control group (77.93±1.18)%, there was significant difference (p<0.01), the recombinant hirudin group with the low-molecular-weight heparin for the treatment of a skin flap survival, the difference was not statistically significant (p<0.05).3 Histology observe:on the first day,the 3group could be observed that there were red blood cell aggregation.On the 5 day,in group A the red blood aggregation has more than the first day and wo also observed that there were some thrombus in the vein.And the red blood aggregation in other group has disappered.4 The acoount of blood capillary Chose the pathological sectioin in each group on 3 and 5 day. Account the blood capillary in five high power visual field and take the mean to be the value.on the third day, the number of the blood capillary in group B and C is 6.9±0.5 and 6.5±0.8,compare with the group A 6.4±0.9, the difference of the number of the blood capillary in the 3 groups has no statistical mean.On the fifth day,the number of the blood capillary in group B and C was significantly higher (11.7±0.8个和10.9±1.1)than group A(5.3±0.9), the difference of the number of the blood capillary in the 3 groups has statistical mean (P<0.05). And there were no significance between group B and C(P>0.05).5 Tissu TXB2 level:Compare to the group B and C, on the third day the level of tissu TXB2 in group A(30.97±1.45) was significantly higher than the group B(25.24±1.50) and group C (24.23±1.36), and the difference between group B C and group A has ststistic maens (P<0.01). On fifth day the level of tissu TXB2 in group B and C is 24.39±0.71 and 22.09±0.51,the group A is 37.21±1.10,the difference between group B C and group A has ststistic maens (P<0.01). On the other days the differenc among the three group has no significance (P>0.05). Conclusion: in this experiment, through local applide hirudin could relif the swelling of the congstion skin flap, significantly reduce the capillary and micro-vein thrombo-sis, red cell aggregation,reduce the tissu TXB2 level,improve the congestion of skin flap...
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