cholesterol/phospholipid ratio.

A catheter(0.3 mm O.D.)was introduced into the external carotid artery(ECA) lumen into the lumen of the internal carotid artery(ICA), then it was gently advanced to the intracranial segment of ICA until the intraluminal catheter was 2~3mm from the origin of MCA. At this point thrombin were injected into ICA to induce thrombosis. Behavior disorders were observed at 3, 6, 12h after the operation. Willis circle, infarct volume and histopathologic changes were examined 12 hours after operation. The results showed that the model had stable behavior disorder score and infarct volume. Mixed thrombus could be observed at the origin of the MCA. Infarction volume of this model was similar with that of the model developed by linear occlusion of MCA in our laboratory. The model has the advantages of easy operation, reliable ischemia and reproducible infarct volume. It may be useful in documenting the safety and efficacy of thrombolytic therapies.

AIM: To study factors affecting the stability of nylon monofilament for intraluminal middle cerebral artery occlusion in rats.METHODS:Successful rates and infarct volume of ischemic model were compared by polyvinyl alcohol (PVA) coated and silicon coated nylon monofilament intraluminal occlusion of middle cerebral artery under condition of ligation and without ligation of peterygopalatine artery.RESULTS:The successful rates were 60% and 53% in two groups under condition of ligation of peterygopalatine artery, and 20% and 27% in other two groups under condition of without ligation of peterygopalatine artery respectively. The intracranial length of nylon monofilament were about 7 mm in successful model and 4 mm in failure model. Animals in the PVA coated nylon monofilament group showed neurological dificit signs earlier, and had a significantly larger infarct volume at 12 hours of ischemia than those in the silicon coated group.CONCLUSIONS:The ligation of peterygopalatine artery is critical in the success of making this kind of ischemic model. The appropriate position of nylon monofilament entering crania and the good expansibility of PVA play an important role in occlusion of blood flow. Because of the relatively lower successful rate, a new substitute with unique quality, proper hardness and better elasticity needs to be explored in the future.