コイの血液凝固能とその検査法

Abstract

In order to establish dependable methods for determining plasma clotting time and to investigate the blood coagulation system in fish, plasma recalcification time (PRT), prothrombin time (PT), activated partial thromboplastin time (APTT) were measured using carp Cyprinus carpio weighing about 350g. Experimental fish were maintained at water temperature ranging from 19 to 24°C and kept in practicable minimum of handling stress during experimental work. Blood samples were collected from the caudal vessels without anesthetization using syringe tipped with 20-gauge needle and then immediately 3.8% sodium citrate solution was added in the amount of 10% of collected blood volume to it. All surfaces of devices were exposed to the blood after siliconization.PRT and PT, indicating intrinsic and extrinsic coagulations respectively, were minimum in incubation at 34°C. PT was more sensitive to temperature variation. These results suggest that extrinsic coagulation system in carp may contain thermolabile clotting factors. PRT and PT were minimum at 25mM concentration of CaCl2 used in the measurement. PRT responded more sensitively to the variation in CaCl2 concentration. PRT was prolonged with the increase of rotation frequency and time in centrifugation, but PT and APTT were not affected by this treatment. PRT and PT were not changeable until about 6hours following plasma separation at 4°C. Afterward, PRT decreased significantly with the lapse of time, whereas PT increased markedly. PRT was variable by the quality of storage vial. Activity of carp tissue thrombpplastin on PT was high especially in brain and heart. The high correlation was observed between activities of rabbit and carp brain thromboplastin on PT.From these results, desirable conditions are as follows; 25mM CaCl2 concentration, 34°C incubation and measurement within about 6hours following plasma separation in plastic vial at 4°C.