Abstract
A decrease of blood fluidity is known to be one of the factors causing cardiovascular disorders. The circulatory system is under the control of the autonomic nervous system and the endocrine system through modulation of peripheral vessel resistance and cardiac output. Furthermore, blood viscosity, which varies according to the state of platelet aggregation, leukocyte adherence and erythrocyte deformability also affect blood fluidity. We have reported that blood fluidity shows dynamic changes by restraint stress, acupuncture stimulation, adrenaline receptor agonists and antagonists. In the present study, the influence of different treadmill running speeds, on blood fluidity and platelet aggregation were examined in the rat. SPF male Wistar rats weighing 150 g were used. The experimental animals were given high or low speed run load about 75 minitues for once a day using a treadmill for animals; in the control group, the same period and environment were given. Blood samples were mixed with heparin, EDTA-2K or sodium citrate as anticoagulant. Blood fluidity was measured with a Micro Channel Array Flow Analyzer (MC-FAN). A PA-20 examined platelet aggregation by the reaction to ADP, which activates platelets for aggregation.The high speed run loaded rats showed a lengthen blood passing time (p < 0.05) and a significant increase of large-sized aggregates of platelets (p < 0.05). High speed run load decreased blood fluidity at least through the increase of platelet aggregation.
