Concurrent administration of cilostazol with donepezil effectively improves cognitive dysfunction with increased neuroprotection after chronic cerebral hypoperfusion in rats

In the present study, we assessed whether concurrent treatment with low doses of cilostazol and donepezil effectively improve memory deficits in association with amelioration of the pathological changes in the white matter of rats subjected to permanent ligation of bilateral common carotid arteries (BCCAL). The escape latency in Morris water maze test was significantly increased at 7, 14 and 21 days in rats subjected to BCCAL. At 21 days after ligation, the white matter lesions including vacuole formation with rarefaction were increased in the optic tract and corpus callosum accompanied by a large increase in glial fibrillary acidic protein (GFAP) immunoreactivity with significantly decreased CNPase-positive oligodendrocytes, all of which were significantly alleviated by the combination therapy with suboptimal doses of cilostazol (30 mg/kg orally) and donepezil (0.3 mg/kg intraperitoneally). The phosphorylated cyclic AMP response element-binding protein (p-CREB)- and Bcl-2-positive cells were significantly decreased following BCCAL, which were completely restored by the combination therapy, whereas the monotherapy with cilostazol or donepezil showed marginal effect. In conclusion, concurrent treatment with cilostazol and donepezil effectively prevented the occurrence of neuropathological alterations in the white matter by activation of p-CREB and Bcl-2, thereby resulting in improvement of spatial learning memory in rats subjected to chronic cerebral hypoperfusion.