Calcium antagonists reduce the extent of infarction in rat middle cerebral artery occlusion model as determined by quantitative magnetic resonance imaging.

Publisher Website
Google Scholar
Abstract
The appearance and evolution of brain infarcts over 3 days following proximal occlusion of the left middle cerebral artery (MCA) in SHR rats were measured non-invasively by magnetic resonance imaging (MRI). Infarcts were clearly visible in coronal, T2 weighted brain sections, 24, 48 and 72 h after MCA occlusion in the left hemisphere, as areas of increased NMR signals. The infarcts were quantified by pixel counting in each section, the sum of 4 sections representing an accurate estimate of the total infarct size. The location and extent of infarction, determined by MRI, were found to be highly reproducible and correlated well with post-mortem histological and biochemical data. A neurological score, made every 24 h, paralleled the evolution of the infarct size, which culminated after 48 h. Pre- or post-treatment of MCA occluded rats with the dihydropyridine calcium antagonist PN 200-110 resulted in a substantial reduction of infarct size, determined by MRI 24, 48 and 72 h after infarction, compared to vehicle treated controls. These findings were corroborated by corresponding improvements of the neurological scores as well as histological and biochemical data. Post-treatment with nimodipine showed qualitatively similar effects. These results support the notion that calcium antagonists, through vascular and/or metabolic mechanisms, are effective in treating acute stroke. Since they were obtained in a chronic, relevant model of stroke with a method directly applicable also to humans, they should encourage further clinical studies with calcium antagonists.