Whole-genome microarrays in the ischemic penumbra of mice and rats 2hrs and 6hrs after permanent middle cerebral artery occlusion (pMCAO)

Neuroprotection has not been successfully translated from animals to humans, and controversies persist about the suitability of animal models for the evaluation of putative stroke therapies. Of these, many appear to be less effective in mice as compared with rats. We hypothesized that this may be due to fundamental interspecies differences in stroke response. Whole-genome microarrays were used to examine differential gene regulation in the ischemic penumbra of mice and rats 2hrs and 6hrs after permanent middle cerebral artery occlusion (pMCAO). The differentially expressed genes in the ischemic penumbra at each time point were compared between the two species. Tissue samples were obtained from the penumbras of rat and mouse brains at 2hrs or 6hrs after pMCAO. Control samples were obtained from similar ipsilateral regions of sham-operated brains of each species. Total RNA was isolated from the tissue samples and analyzed by microarray analysis. For microarray analyses 24 animals were used [1 animal/microarray, n=3/group, 8 groups: Sham (SP) or MCAO (MP) in rats or mice at 2 hrs and 6 hrs, respectively].