Munro R, Hechtel F O, Sawyer R T
Haematology Department, Morriston Hospital, Swansea, UK.
Thromb Haemost. 1989 Jun 30;61(3):366-9.
The bite of the medicinal leech bleeds for many hours. For decades it has been assumed that the remarkably prolonged bleeding time of a leech bite wound is due to hirudin, a specific anti-thrombin secreted by the leech during feeding. By measuring haematological parameters of blood oozing from a leech bite wound on 15 different occasions in 7 human volunteers, we demonstrate that the hirudin-sensitive coagulation parameters, including thrombin-induced platelet aggregation, are prolonged for only 15 min, after which they return to normal. This suggests that excess hirudin secreted by the leech is washed out during this period. However, bleeding from the leech bite wound persists for a mean of 10 h. Platelets in smears of exuding blood show no evidence of spontaneous aggregation, but in vitro platelet aggregation can be induced by exogenous collagen at any time. In view of sustained bleeding in the apparent absence of hirudin, attention is focussed onto an unsuspected factor or factors which may better explain the prolonged bleeding phenomenon.
医用水蛭叮咬后会出血数小时。几十年来，人们一直认为水蛭叮咬伤口出血时间显著延长是由于水蛭素，即水蛭在进食过程中分泌的一种特定抗凝血酶。通过在7名人类志愿者身上15次不同情况下测量水蛭叮咬伤口渗出血液的血液学参数，我们证明，包括凝血酶诱导的血小板聚集在内的对水蛭素敏感的凝血参数仅延长15分钟，之后便恢复正常。这表明在此期间水蛭分泌的过量水蛭素被冲洗掉了。然而，水蛭叮咬伤口的出血平均持续10小时。渗出血液涂片上的血小板没有自发聚集的迹象，但体外血小板聚集可在任何时候由外源性胶原蛋白诱导。鉴于在明显没有水蛭素的情况下仍持续出血，人们将注意力集中在一个或多个未被怀疑的因素上，这些因素可能能更好地解释出血延长现象。
