The Expression And Correlation Of Neural Restrictive Silencer Factor And Synaptophysin In The Hippocampus Of Rats With Vascular Dementia

Objective:Vascular Dementia(Va D) refers to a syndrome of acquired mental retardation caused by various cerebrovascular diseases, one of the most common types of the old age Dementia. The incidence of Va D is increasing year by year, which has gravely affected the quality of human life. At present, one study found cerebral ischemia may impair the hippocampus of learning and memory cricuit, which is the main factor of vascular dementia. Synaptophysin(SYP), one of the neurobiological mechanisms, affects the ability of learning and memory. According the reports, the SYP gene can be controlled by neural restrictive silencer f actor(NRSF) in vitro. As a transcription factor, NRSF plays an important role in neurogenesis and nerve system disease. NRSF expression level and repression target genes vary within different physiologic and pathological circumstances. This study intents to provide a new vision for preventing and treating Va D by investigating gene and protein expressions of NRSF and SYP in the hippocampus of Va D rats.Methods: 2 months unpregnant female Sprague-Dawley(SD) rats were randomly divided into the control group and the model group. The model rat with Vascular Dementia was established by permanent ligation of bilateral carotid arteries(2VO). Morris water maze was adopted to test the ability of learning memory of the two groups rats. The m RNA and protein expressions of NRSF and SYP were determined by reverse transcription-quantitative polymerase chain reaction(RT-q PCR), Western blotting and Immunofluorescence. Electrophoretic mobility shift assay(EMSA) was used to verify the binding activity of NRSF protein combined with NRSE probe between the two groups.Results: The average speed of the two groups rats had no difference(P>0.05); the average escape latency period in the model group was significantly higher than those of the rats in the control group(P<0.05); the proportion of tendency and straight tactics of the model group reduced in the third, fourth and fifth days when compared with the control group(P<0.05), but there was no significant difference in the first and second days(P>0.05); the immunofluorescence results showed that the positive reactant of NRSF was co-localized with in nuclei in the hippocampus of the control group and model group, the positive reactant of NRSF in the model group was brighter than the control group, and the positive reactant of NRSF also distributed in the neurites of CA1 and CA3 regions of the model group, the SYP positive reactant showed fluorescent brightness of the model group was weaker than the control group, and the positive reactant of SYP located out of the nucleus in the model group and control group; the m RNA and protein of NRSF expressions in the hippocampus of the model group were significantly increased(P<0.05); however, the SYP m RNA and protein expressions in the hippocampus of the model group were obviously lower than these of in the control group(P<0.05); the nuclear-cytoplasmic ratio of NRSF in the model group was significantly high when compared to the control group(P<0.05); we found a negative correlation between the total NRSF and SYP m RNA expression(r2=-0.546,P<0.05), and there was a negative correlation between the nuclei NRSF and SYP m RNA expression(r2=-0.825,P<0.05); meanwhile, EMSA result showed that the optical density value of NRSF-NRSE combined in the model group was higher than the control group(P<0.05).Conclusion: In the hippocampus of permanent ligation of bilateral common carotid artery rats the expression of NRSF m RNA and protein increase, the SYP protein and m RNA decrease; There is a obvious negative correlation between NRSF protein and SYP m RNA.