Vincent A Dinapoli | PubMed Health

PubMed2006

Selective MCA occlusion: a precise embolic stroke model.

The present study describes a method for improving the precision and accuracy of clot placement within the middle cerebral artery (MCA) of rats, utilizing a micro-catheter and laser Doppler flowmetry. This technique reduces the size of clot needed to achieve stable occlusion with no failed embolizations and a low percentage of early recanalizations. Infarctions were consistent in both size and distribution within the MCA perfusion territory. Selective embolization in aged animals (n = 10) resulted in substantially larger infarctions than those seen in aged animals (n = 10) following non-selective embolization (P < 0.05), or young animals (n = 10) subjected to filamentous occlusion (P < 0.001). Clots were localized to the MCA by direct examination at 0, 60 and 120 min post-embolization (n = 14). All aged animals surviving 24h exhibited moderate to severe functional deficits, with selectively occluded animals having a higher mean score on the modified neurologic severity scale (P = 0.002). This model provides a highly reproducible method for embolization of the MCA and reliable reperfusion with rt-PA.

Aging↗

PubMed2005

Influence of age on stroke outcome following transient focal ischemia.

OBJECT: More than 100 clinical trials based on animal models have failed to identify a clinically effective neuroprotectant for stroke. Current models of stroke do not account adequately for aging nor do they incorporate the use of female animals. The authors evaluated the pathological and physiological differences in stroke in young, adult, and elderly female rats. METHODS: Three groups of female Sprague-Dawley rats were studied. Nine rats were divided into three groups: young (3 months); adult (9 months); and elderly (18 months). Intraluminal filament occlusion was performed for 120 minutes while cerebral blood flow was monitored. Physiological parameters were assessed. Infarction volumes were quantified at 24 hours. The mean arterial pressure increased in the young animals (103 +/- 3.51 mm Hg; p < 0.001) during occlusion and decreased in the elderly group (65.56 +/- 3.03 mm Hg; p < 0.01). Cortical and striatal infarction volumes in the elderly animals were substantially larger (p < 0.05). Young animals exhibited a lesser decrement in cerebral blood flow (p < 0.05) during ischemia. CONCLUSIONS: This study reinforces the importance of using older animals for the researching and treatment of stroke. Elderly animals show differences in response mechanisms, ischemic consequences, and histological changes. These differences may partially explain the current lack of success involved in using young-animal models to predict the clinical efficacy of neuroprotective agents.

Age Factors↗