Thrombolytic Evaluation of Modified Photochemical Middle Cerebral Artery Thrombosis in Rats

Objective To evaluate modified photochemical middle cerebral artery (MCA) thrombosis experimental model in the research of thrombolysis. Materials and Methods He-Ne laser and hematoporphyrin derivative were used to induce thrombus in MCA of rats. During the procedure, bilateral common carotid arteries were occluded for 60 minutes. The dynamic development of the thrombus was observed with electron microscope, while the development of the infarction lesion was observed with both optical and electron microscope as well as MRI. After intravenous injection of urokinase (UK), the thrombolysis process was watched directly under the operating microscope. Results Under operating microscope, the development of white thrombus in the occluded MCA could be watched, which was platelet thrombus under optical microscope. The fibrin was increasing with the lapse of time, and large amounts of fibrin formed network structure in 24 hours after MCA occlusion, which was similar to the platelet fibrin thrombus observed in human cerebral infarction. The preparation of infarction lesion was reproducible and its optical and electron microscopic features were similar to that in human beings. The thrombus could be dissolved with UK. Conclusion The modified photochemical thrombosis model of MCA in experimental rat is an ideal animal model which can be used for the research of thrombolysis.