Preconditioning as a method of neuroprotection in a model of brain infarct

Preconditioning of ischemic and hypoxic type was investigated as a method of protecting brain against acute ischemic injury. The preconditioning methods were applied to experimental rats 24 h before the time when local brain infarct was done by middle cerebral artery occlusion (MCAO). It was found that the ischemic and hypoxic preconditioning resulted in three general morphological changes: 1) the size of infarct zone was reduced by 2.2–3.8 times compared with rats that had not been treated with the preconditioning before MCAO; 2) the preconditioning treatment retained the number of living neurons in penumbra at the level of control rats, while without the preconditioning neuronal count in the penumbra after MCAO was 29% lower; 3) the number of glial cells in penumbra was increased after MCAO by 38% compared with the control level, and continued to increase under the preconditioning treatment up to 60%, that suggests an important role of neuroglia in neuroprotection. Selective blockers of ATP2dependant K+2channels (52hydroxydecanoate and glibenclamide) completely abolished the neuroprotective effects of the preconditioning.