A novel guinea pig model with cyclic flow reductions following thrombotic cerebral ischemia.

Cyclic flow reductions (CFRs), a phenomenon indicated with repeating rethrombosis following thrombolysis in clotted vessel has been observed in coronal, carotid and popliteal arteries in various species when they were occluded with vessel damage, suggesting the presence of CFRs in the acute phase of stroke in man. Although much effort has been directed toward rethrombosis or ischemia-reperfusion injuries in acute strokes, a therapy for CFRs in strokes has not been established because of the lack of ideal animal models. We have established a novel guinea pig model with CFRs in the middle cerebral artery (MCA) using a photothrombotic technique, in which the MCA was spontaneously recanalized within 20 min after the first occlusion with subsequent CFRs. We also investigated the effects of antiplatelet agents and the anticoagulant heparin using this model. All tested antiplatelet agents inhibited CFRs, whereas an anticoagulant did not. These results show that this model is unique with respect to its development of MCA cyclic flow reductions, and may be suitable for investigating mechanisms and therapeutic reagents of CFRs in the MCA.