Experimental Study On Exacerbation Of Hippocampus Neuronus Injury Caused By Diabetes In Vascular Dementia Rats

OBJECTIVE To study the effect on cognitive ability and the neuronal injury caused by diabetes in VaD rats. METHODS 1. The diabetic rats were induced by streptozotocin and permanently ligated the bilateral common carotid arteries. Estimated the spacial study and memory ability in Y-maze and observed the morphology of hippocampus. The expression level of CDK5/p35 in CAl area of hippocampus and CDK5 activity were estimated; 2. Hippocampal neurons were exposed to hypoxia bind hyperglycemic environment, the neuronal survival ability, the expression level of CDK5/p35 and CDK5 activity were estimated. RESULTS 1.The VaD rats in diabetic group had worse performance in Y-maze, more neurons with serious injury, more neuronal apoptosis and lower expression level of CDK5 in hippocampus CAl area than other groups, while the expression level of p35 and CDK5 activity were increased. 2. Comparedwith other groups, the neuronal survival ability, the expression level of CDK5 mRNA and protein decreased significantly in hypoxia bind hyperglycemic group ,while the expression level of p35 and CDK5 activity increased. CONCLUSIONS The cognitive dysfunction of learning and memory induced by VaD had been deteriorated by diabetes. The hippocampus neurons injury induced by hypoxia could be deteriorated by hyperglycemia. It indicated that the deficiency of CDK5 and increased level of p35 and CDK5 activity may play an important role in the mechanism of cognitive dysfunction and neuronal damage.