Cerebral Activities in Rats within Different Periods after Experimental Unilateral Cerebral Ischemia

摘要

A model of cerebral ischemia in the left hemisphere was established in rats by occlusion of the left middle cerebral artery (MCAO). Twenty-five Sprague-Dawley rats were divided into five groups, the control (C) group and animals 4, 24, 48h, and one week (4h, 24h, 48h, and 1w, respectively) after MCAO. The footprint pattern test (FPT) was used to compare the gait in the MCAO groups with that in the C group. Ongoing EEGs were recorded and analyzed (spectral power densities of different rhythms were calculated). Somatosensory evoked potentials (SSEPs) were induced by stimulation of the right median nerve and averaged. Rats of group 4h displayed significantly worse gait parameters compared to those in the C group (P < 0.01). The 24h, 48h, and 1w groups demonstrated no significant differences from this aspect, as compared with the C group (P > 0.05). Compared with the latter group, mean EEG mean powers of the EEG rhythms in the MCAO groups were significantly lower (P < 0.01), latencies of the SSEP components were longer, and peak amplitudes were reduced significantly (P < 0.01). All EEG and SSEP parameters demonstrated trends toward normal values with increase in the time interval after MCAO but were not restored completely. Therefore, functional behavioral tests, EEG, and SSEP monitoring at different phases after experimental cerebral ischemia can provide detailed valuable information on the states of neural activities, which are well correlated with the motor function recovery.