Mouse Model of In Situ Thromboembolic Stroke and Reperfusion

Abstract

Background and Purpose-Early reperfusion using tissue-type plasminogen activator is the only therapeutic agent to treat focal cerebral ischemia with proven efficacy in patients. Nevertheless, novel insights into the pathophysiology of neurons, glial cells, and the fate of the endothelium after stroke call for the use of new strategies to improve stroke treatment alone or in combination with tissue-type plasminogen activator-induced thrombolysis. Unfortunately, despite the plethora of drugs that display clear beneficial effects in animal models of experimental ischemia, their subsequent use in clinical trials has proven disappointing. As such, one is forced to consider that new animal models of focal cerebral ischemia may be required before clinical evaluation of a new molecule. Methods-In situ microinjection of purified murine thrombin was used to trigger a local clot formation in anesthetized mice. Cerebral blood velocity was measured continuously throughout the duration of the study. The efficiency of recombinant tissue-type plasminogen activator to induce thrombolysis and its subsequent effect on infarct volume were then measured. Results-In situ thrombin injection leads to a reproducible clot formation and cortical brain injury. Recombinant tissue-type plasminogen activator-induced thrombolysis reduced infarct volume by 36.8% when compared with untreated control mice. Conclusions-We describe an original and reproducible mouse model of in situ clot formation and reperfusion, which could be used to investigate new therapeutic strategies to improve stroke treatment.

A Novel Embolic Model of Cerebral Infarction and Evaluation of Stachybotrys microspora Triprenyl Phenol-7 (SMTP-7), a Novel Fungal Triprenyl Phenol Metabolite

“…Next, we examined whether t-PA ameliorates the effects of the cerebral infarction in this model by analyzing the CBF, infarction area, and neurological scores. These data suggest that the embolus is dissolved by treatment with t-PA. Our model is in agreement with the data reported from animal models (25,26) and clinical trials (27). More importantly, in our model, the embolus is formed in an artery, although it is formed outside the body in the conventional models.…”

Thrombotic distal middle cerebral artery occlusion produced by topical FeCl3 application: A novel model suitable for intravital microscopy and thrombolysis studies

“…The latter model is further complicated by the highly variable distribution of emboli. Recently, a novel distal MCA occlusion model produced by microinjection of thrombin into the MCA lumen has been reported (Orset et al, 2007). The thrombin model, based on producing a clot within the distal MCA, shares the same features with our model and offers the same advantages, except that thrombin is more expensive compared with FeCl 3 , preparation of the micropipette requires special equipment, and expertise is required for the All mice were kept normothermic at 371C ± 0.11C.…”

“…Ten minutes after topical application of 10% FeCl 3 , intravenous tPA (Actilyse; INN alteplase, Boehringer Ingelheim, Ingelheim am Rhein, Germany) administration was started. Overall, 10% of the typical murine dose (10 mg/kg) (Kilic et al, 2000;Orset et al, 2007), which is B10 times higher than the human dose, was injected as a bolus and the remainder as a continuous infusion over a 30-minute interval using a syringe infusion pump (NE-1000, New Era Pump Systems, Farmingdale, NY, USA) (n = 26). A 10-minute time point was chosen to allow enough time for clot formation and MCA occlusion based on the observation that rCBF decreased to ischemic values within 10 minutes after FeCl 3 application (Figures 2 and 3).…”

Modeling Stroke in Mice: Permanent Coagulation of the Distal Middle Cerebral Artery

“…However, a previously described thromboembolic stroke model 26 provides the option for a complimentary stroke model with reperfusion of cortical brain ischemia. Taken together, the high reproducibility, the possible longterm observation due to minimal mortality and the comparable relative infarct volume and localization in respect to human stroke distinguish the "coagulation model" as a valuable model for basic and translational stroke research.…”