Effects of dihydroergotoxine on the change of NOS positive neurons in hippocampus and cerebral cortex of mice with vascular dementia

Objective: To investigate the change of nitric oxide synthase (NOS) positive neurons in hippocampus and cerebral cortex of mice with vascular dementia (VD) and the effects of dihydroergotoxine on VD. Method: The mice were subjected for ischemia-reperfusion repeatedly by blocking the bilateral common carotid arteries to establish the VD models. Animals with the shamed-operation were taken as control group. The treating group was administrated with dihydroergotoxine after the establishment of VD model. The behavior changes were observed through the step-down avoidance test and water maze test on the 7th, 14th and 30th days after operation, respectively. A NADPH-diaphorase histochemistry method was used to measure the NOS positive neurons in hippocampus and cerebral cortex of mice. Result: The NOS positive neurons in hippocampus and cerebral cortex of VD group decreased more than those of control group on the 7th day after operation, and those of treating group increased more than VD group, while no significant difference was found (P0.05). With the prolongation of observing time, the NOS positive neurons of VD groups reduced significantly than those of control groups on the 14th and 30th day after operation(P0.01), but with using dihydroergotoxine, the NOS positive neurons of treating groups was apparently higher than those of VD groups(P0.01). Conclusion: Fewer NOS positive neurons in hippocampus and cerebral cortex during a relatively long time might participate in the pathogenesis of VD. Dihydroergotoxine might increase the NOS positive neurons in hippocampus and cerebral cortex and improve the clinical symptoms of VD.