The coagulation hemostasis dynamics in rats in the post-ischemic time

Abstract

Introduction. Ischemic injury to the endothelium influences on a coagulation hemostasis, worsening hemodynamics of cerebral microcirculation as a result of rheological occlusion. The long-term post-ischemic blood clotting system changes are not studied well by now.The work purpose – to study a coagulation hemostasis and endothelial prostacyclin – synthetic activity of pial vessels within 21 days after single short-term transient cerebral ischemia in rat.Material and Methods. Ischemia was reproduced by means of 12-minute time occlusion of both carotids with the simultaneous arterial hypotension. Post-ischemic changes were investigated in 4 groups of rats: on the 3rd, 7th, 14th and 21st day after ischemia. The state of blood clotting system was estimated on time of clot formation in the blood plasma by an automatic optical method with use of screening tests of definition of prothrombin and thrombin clotting time and concentration of fibrinogen. Endothelial prostacyclin – synthetic activity was estimated by pial vessel reaction to indometacin.Results. On the 3rd day after ischemia the increase in prothrombin time was observed. Level of fibrinogen increased on the 3rd and the 14th days of the post-ischemic time. On the 21st day after ischemia thrombin time decreased. The inverse correlation of pial vessel endothelial prostacyclin – synthetic activity with the fibrinogen level and direct correlation with vessel cross-sectional area of these vessels is established.Conclusions. Short-time global cerebral ischemia causes changes of blood clotting system mechanisms lasting for 21 days of the post-ischemic time. Post-ischemic abnormalities in hemostasis system are connected with changes in endothelial prostacyclin – synthetic activity of cerebral vessels that, along with decreased anti-aggregation ability of vascular system, is also the reason of narrowing of the lumen in pial vessels.