The Expression Of C-jun MRNA In Rat Brain After Cerebral Multiple Infarct And Multi-infarct Dementia

The expression of c-jun mRNA in rat brain after cerebral multiple infarct and multi-infarct dementiaIntroductionMulti-infarct dementia (MID) is a group of syndrome that the main clinical feature is dementia which caused by a number of infarct, is one of the most common subtype of vascular dementia. With increased population advanced age in the world, multi-infarct dementia has a serious impact on the health and quality of life.Immediate early genes (IEGs) are a class of genes belongs to proto-oncogene family which are induced by the second messenger, and make rapid response to stimuli. C-jun is one of immediate early genes which reside in the central nervous cells generally. The expression of c-jun was in a low level under normal circumstances and difficult to detect. After focal or global cerebral ischemia, the expression of c-jun increased significantly in a time-dependent manner.Currently, there are a lot of reports about the expression of c-jun after cerebral ischemia-reperfusion, but it is few report about the expression of c-jun on cerebral multiple infarct and multi-infarct dementia. So we make rat cerebral multiple infarct and multi-infarct dementia model by the modified microemboli method. Observe the expression of c-jun mRNA in the brain of cerebral multiple infarct and multi-infarct dementia rat with in-situ hybridization method and analysis the regularity, and further provide a price value of the research data for the possible mechanism study of c-jun in cerebral multiple infarct and multi-infarct dementia. Materials and Methods一,Animal and groupingMale Wistar rats weighting 350±50g provided by animal experiment center ShengJing hospital. The animals were distributed to groups as follow: Normal group; Sham group; 2h,4h,24h,5d,7d,15d,24d,30d after infarct group, and 2h,4h,24h,5d,7d after infarct groups are included in multiple infarct group(each group n=8), thenl5d,24d,30d groups are subdivided into multi-infarct dementia group(each group n=8) and multiple infarct but not dementia group according to results of the Morris water maze test.二,Materialsc-jun in-situ hybridization kit; TTC kit三,Methods1,Make cerebral multiple infarct and multi-infarct dementia model by microemboli method (omogenous microemboli were injected into internal carotid artery)2,TTC staining to indentify the infarct3,Morris water maze to indentify whether the model is dementia4,Detect the expression of c-jun mRNA at each time point by in-situ hybridization method, and observed continuouslyResults一,TTC stainingNormal brain tissue is red. In multiple infarct group punctiform and lamellar white areas can be seen.二,Result of Morris water mazeIn the acquisition trails, the performance record of multi-infarct dementia rats lags, compared with the normal group rats. In the space exploration trails, the frequency of rats going straight through the platform is lower in the dementia group than that in normal group.三,The brain tissue sect ion HE staining observed in Iight microscopeCells in brain cortex of normal group have normal form and structure. In multiple infarct group, the number of neurons decrease,lay in disorder,the peripheral diastema of cell widen, a lot of neurons become necrosis,body swelling,staining blandly,nuclei dissolve and structure not clear, all these occurs in cortex,infracortical medulla and basal ganglia region, and have many contract neurons in infarct peripheral region.四,The expression of c-jun mRNAC-jun mRNA expressed little in normal rats, and increased a little in sham group, without significant difference compared with the normal group, p>0.05; After cerebral multiple infarct, c-jun mRNA increased greatly, especially in cerebral cortex and hippocampus, with significant difference compared with the normal group and the sham group, p<0.05; Observed continuously, the number of c-jun mRNA increased after 2 hours after infarct, keep on 1 week, p<0.05. In the multi-infarct dementia group and cerebral multiple infarct but not dementia group after 15d,24d,30d infarction, the expression of c-jun mRNA has no significant differences compared with the normal group and the sham group, p>0.05. There is no significant difference of the expression of c-jun mRNA between multi-infarct group and cerebral multiple infarct but not dementia group, p>0.05.DiscussionAt present, scholars established many animal models to aim directly to cerebral multiple infarct and multi-infarct dementia; but they have advantages and disadvantages respectively. In our study, we get cerebral multiple infarct and cerebral multi-infarct dementia model by microemboli method (omogenous microemboli were injected into internal carotid artery). Indentify by TTC staining,HE staining,Morris water maze test shows that we made the cerebral multiple infarct and multi-infarct dementia model successfully. The model simulates a good clinical thrombosis way into the brain, and appropriately mimicry clinical ischemic stroke pathogenesis, and it is conductive to investigate the pathophysiological mechanisms of cerebral multiple infarct and multi-infarct dementia; but the drawback is that the method is more complex.Immediate biochemical reaction can occur after focal/general cerebral ischemia. Immediate early genes expression increased a few minutes after ischemia. This study shows that: the normal group and sham group rats have a little brain c-jun mRNA expression, but there are no significant differences between them. The expression of c-jun mRNA increased in all groups of cerebral multiple infarct groups in rats. The data has significant differences compared with the normal group and the sham group. Observed continuously, c-jun mRNA increased 2 hours after infarct, keep on 1 week. In the multi-infarct dementia group and multiple infarct but not dementia group after 15d,24d,30d infarct, the expression of c-jun mRNA has no significant differences compared with the normal group and the sham group, and there is no significant difference between them. These results suggest c-jun mRNA only expressed in the early period of cerebral multiple infarct. When the later period of cerebral multiple infarct or multi-infarct dementia formatted, the expression of c-jun mRNA has been significantly reduced. However, these results may correlate with few animal cases, different experimental model, et al.Conclusion1,In our study, we make cerebral multiple infarct and cerebral multi-infarct dementia model by microemboli method (omogenous microemboli were injected into internal carotid artery). Many tests show that the model is successful.2,C-jun mRNA showed a regularitily over-expression after cerebral multiple infarct, but no significant changes in cerebral multi-infarct dementia group.