| Objectives Through took the injection by autophagy inhibition(3-methyladenine),autophagy excited drug(rapamycin) to the lateral ventricle of vascular dementia rats model, Morris water maze tested the ability of learning and memory in rats,detected the expression of autophagy specific protein and synaptic plasticity related proteins, and then investigated the effect of autophagy on the expression of synaptic plasticity in rat hippocampal CA1 region proteins associated with vascular dementia, and provided a theoretical basis for the pathogenesis of vascular dementia and treatment and prevention.Methods 1 A total of 192 SD rats were randomly divided into sham group(Sham),Vascular dementia model group(VD), Autophagy inhibitor(3- methyl adenine) group(3-MA), autophagy agonist(rapamycin) group(Rap). Each group was divided into 1week,2weeks, 4weeks, 8weeks subgroups after the success of model preparation(n=12). 2Model preparation: Vascular dementia rat model were established by improved Pulsinelli four vessels block(4-VO), that was to say coagulated bilateral vertebral arteries permanently and made bilateral common carotid artery occlusion repeatedly. While sham group only exposed bilateral vertebral artery and common carotid artery, not to block blood flow. 3 Delivery methods: autophagy inhibitors(3-methyl adenine) group and autophagy agonist(rapamycin) group of rats were injected Lateral ventricle injection of 3- methyladenine or rapamycin 30 min before modelmaking. 4 We evaluated the changes of learning and memory of rats with the Morris water maze. 5 Immunohistochemistry was used to detect the expression of the CA1 of rat hippocampus of autophagy related protein microtubule associated protein 1 light chain 3 II(MAP1-LC3 II, LC3II), Western blot was the way we detected the CA1 region of hippocampus of autophagy related protein LC3II/LC3 I expression ratio; immunohistochemistry and immune Western blot was used to detect the related proteins synaptic plasticity related proteins in rat hippocampal CA1 region proteins, including synaptophysin(Syn), postsynaptic density95( PSD-95), growth associated protein 43(GAP-43), microtubule associated protein 2(MAP-2). 6 We observe tissue slices with microscope camera OLYMPUS(400×), then analysis them by Motic Med 6.0 digital medical image analysis system. The results of Western Blot were analyzed with Image J. 7 Data were analyzed using statistical software SPSS17.0, measurement data with the mean ± standard deviation(sx ±), Multiplecomparison of the means between the groups using single factor analysis of variance(one-way ANOVA),said the two groups were compared using the t test, to determine the relationship between two variables,we used Pearson correlation analysis method for correlation analysis, P<0.05 for the difference was statistically significant.Results Compared with Sham group, VD group at each time point to observe the escape latency at 1 day did not change significantly(P>0.05), the escape latency of the observation time was longer than that of group Sham, the difference was statistically significant(P<0.05 or P<0.01) after the second day, the number of crossing the original platform were lower than Sham group(P<0.05); compared with VD group, 3-MA group of rats at each time point of the escape latency at 1 day did not change significantly(P>0.05), second day after each test time escape latency was shortened, the difference was statistically significant(P<0.05 or P<0.01), crossing the original platform number were increased(all P<0.05); compared with VD group, Rap group of rats at each time point of the escape latency at 1 day did not change significantly(P>0.05), second day after each test time escape latency was prolonged, the difference was statistically significant(P<0.05 or P<0.01), the number of crossing the platform were decreased(all P<0.05). 2Compared to sham group,the expression of LC3 II and LC3II/LC3 I was elevated at 1w in VD group, and reached maximum level at 4w, subsequently decreased at 8w, the difference was statistically significant(P<0.01); compared with group VD, the expression of LC3 II and LC3II/LC3 I was lower in 3-MA group at different time points, the difference was statistically significant(P<0.05 or P<0.01); and the expression of LC3 II and LC3II/LC3 I in Rap group at different time points was higher than VD group, the difference was statistically significant(P<0.05 or P<0.01). 3 Compared with Sham group,the expression of Syn, PSD-95, MAP-2 protein decreased, GAP-43 protein of VD group was increased at each time point, the difference was statistically significant(P<0.01);compared with VD group, the expression of Syn, PSD-95, MAP-2 protein in 3-MA group at different time points was higher than VD group, there are statistically significant difference(P<0.05 or P<0.01); compared with VD group, the expression of Syn, PSD-95,MAP-2 protein in Rap group at different time points was lower than VD group, the difference was statistically significant(P<0.05 or P<0.01). 4 The correlation analysis results showed that autophagy related protein LC3 II or LC3II/LC3 I were negatively correlated with synaptic plasticity related proteins(P<0.01); there was no significant correlation between autophagy related protein LC3 II and GAP-43 protein(P>0.05).Conclusions 1 Autophagy involved in the pathogenesis of vascular dementia, Thelearning and memory dysfunction increased autophagy may add major rats to a certain extent. 2 Synaptic plasticity associated proteins play an important role in the pathogenesis of vascular dementia, decreased the expression of synaptic plasticity related proteins may aggravate the ability of learning and memory disorder rats. 3 The expression of synaptic plasticity related protein may be inhibited by autophagy in hippocampal CA1 area of rats with vascular dementia, Autophagy increased may inhibit the expression of synaptic plasticity in rat hippocampal CA1 region proteins associated with vascular dementia in some degree, and this mechanism may make the learning and memory dysfunction in rats worsen. |
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