The Clinical Characteristics Of Vascular Cognitive Impairment And The Basic Research Of The Relationship Between Cognitive Impairment And Neural Regeneration

Background and ObjectiveWith the medical development and social aging, early diagnosis of the cognitive impairment and effective measures to reverse the progression are vital for the whole society. In 2006, the proclamation of world stroke day pays great attention to recognize, treat and prevent vascular cognitive impairment (VCI). From this, we can see that cognitive impairment caused by cerebral ischemia has already revoked the scholars' attention.Cerebral ischemia can cause degeneration and necrosis of the nerve cells in cortex, subcortex and hippocampus which damage the nerve fibre circuit of memory, executing skills and orientation, thus resulting in cognition deficits. The regeneration of central nervous system can reestablish the synaptic connections. The repair of the nerve fibre circuit can significantly improve the cognitive function. Recent researches of the central nervous system regeneration are concentrated in Nogo protein and its receptor NgR. However, as research methods and observation time were different, the conclusions were not in accordance with each other.By investigating the clinical characteristics of VCI and detecting the relationship between cognitive impairment and neural regeneration, we hope this research can find new method of early diagnosis and treatment of VCI.Materials and Methods 1. For the study, patients conforming VCI standard admitted to neurological department of the First Affiliated Hospital of Zhengzhou University from January, 2005 to December, 2006 were selected. The VCI group and control group included 30 patients respectively. Both groups used Mini-Mental State Examination (MMSE) to test the neuropsychology and computerized tomography (CT) to evaluate the degree of brain white matter demyelination.2. The rats were divided into three groups at random: normal group, sham operated group and model group. Each group was divided into three subgroups by 15days, 30days and 60days. The cerebral ischemia models were produced by permanent occlusion of the bilateral common carotid arteries. All of the rats were trained in Morris Water Maze to test the changes of ethology. The expression of Nogo-A and NgR were measured by immunohistochemical technique.Reults1. MMSE scale of VCI subjects showed they had significant deterioration (P<0.01)in the subtests of visuospatial skills, orientation to time and place, memory, executing skills and language. The VCI group had significant white matter demyelination than the control group(P<0.01).2. The expression of Nogo-A and NgR in model group were significantly higher than that of sham operated group and normal group at the same timepoint (P<0.01). All of these changes were conformed to the changes of ethology. In model groups, the masculine expression of Nogo-A in 60 days is lower than that in 15 days(P<0.05); the masculine expression of NgR in 60 days is lower than that in 30 days(P<0.05).ConclusionPatients with VCI showed different degrees of deterioration in visuospatial skills, orientation to time and place, memory, executing skills and language which were accompanied with evident white matter demyelination. As the principal cause of demyelination, cerebral ischemia causes up-regulation of the expression of Nogo-A and NgR in the brain of rats, which may be the first principal cause of cognitive impairment.