Persistent impairment of gait performances and working memory after bilateral common carotid artery occlusion in the adult Wistar rat

Background: The clinical and pathophysiological effects of a chronic reduction of cerebral blood flow in humans are not completely known. We investigated whether rats subjected to bilateral common carotid artery occlusion (bCCA-o) developed focal neurological deficits, gait dysfunction, and working memory alterations. Methods: Eighteen male Wistar rats were subjected to bCCA-o, 13 were sham-operated. We assessed sensorimotor functions, gait on a 60 cm-long elevated bridge, and working memory (object recognition and Y maze tests) before and 30, 60, and 90 days after surgery. Histological analysis was performed in a subgroup of 10 rats. Results: No rat showed sensorimotor alterations after surgery. Although gait performances of both bCCA-o and sham-operated rats declined over time, the differences reached statistical significance only for the bCCA-o group (mean SE: 26.8+/-5.0; 22.4+/-4.9; 24.5+/-5.5 cm at 30, 60, and 90 days, respectively) in comparison with baseline (52.9+/-5.2 cm; P<0.05). At 60 and 90 days, bCCA-o rats in comparison with sham-operated rats showed decreased performances on object recognition (discrimination index: 0.15&PLUSMN;0.03 vs. 0.29&PLUSMN;0.05 at 60 days and 0.10&PLUSMN;0.04 vs. 0.41&PLUSMN;0.07 at 90 days; P<0.05) and on Y maze test (alternating rats: 9.9 vs. 85.7% at 60 days and 16.6 vs. 100% at 90 days; P