The Expression Of C-fos In Brain After Cerebral Multiple Infarct Dementia Of Rats

The Expression of c-fos in Brain after Cerebral Multiple Infarct Dementia in RatsIntroductionMultiple infarct dementia (MID) is a subtype of vascular dementia. It is a group of clinical syndrome which caused by multiple infarct, following disorder of intelligence and cognition ability. The incidence of cerebrovascular disease rise year by year with increased population advanced age in the world, so the incidence of multiple infarct dementia rise. MID not only damage health of patient and affect quality of life of patient, but also increase the burden of society and family, so more and more people pay close attention to it in world. It is also one of important study in gerontal medical domain. The pathomechanism of MID is ischemic or hypoxia leading to damage of specified nervous tissue related with cognition ability. The molecule mechanism of MID is damage after ischemic, which is a complicated patho-physiology process. Some studies have shown that ischemic can make cerebral cell cascade of damage, may arouse mechanism of cell death. The occurrence of cascade of damage after ischemic may involve in 4 different phases: energy failure or excitatory amino acids toxicity,peri-infarct depolarizations,inflammatory reaction,programmed cell death or apoptosis.The learning and memory are important function of mankind and animal and also high grade integration function of central nervous system. The learning is the process of nervous activity that people or animal receive changing information, and obtain knowledge (new behavior custom or experience). While the memory the process of nervous activity to store and readout acquired knowledge. The learning and the memory are interconnection nervous process. The encephalic regions of learning and memory are temporal associated cortex,hippocampus,thalamencephal,limbic system and so on. The temporal associated cortex and hippocampus are important encephalic regions of learning and memory.Immediate-early genes are considered as third messenger intranuclear, which connect extracellular signal with the expression of effector long time, and become transcription dependence template.C-fos gene was a encoded neucleoprotein which was found first. C-fos implement its function by Fos neucleoprotein:①third messenger: Fos is regulating factor intracellular, playing important role in signal convery.②neuron protection: the expression of c-fos occur in survival neuron after earlier period of ischemic, take part in early reaction after neuron damage.③Fos is the depressor for the expression of c-fos.④In normal, c-fos involve in cell growth,cell differentiation,information transfer,neural plasticity and learning and memory and so on; but in pathological condition, the expression and regulation of c-fos correlated with the occurrence and development of some diseases.The final ethological appearance of MID animal model is learning and memory deficit, so study for MID is to study learning and memory. Many empirical study show the expression of c-fos increase in learning and memory process, especially in long-term memory process. Many study find the expression of c-fos in brain after cerebral infarct, which show c-fos may take part in the development process of cerebral infarct and MID.Material and Methods一,Material(一)Animal and groupingHealthy male Wistar rats weighing 300-400g were distributed to 3 groups at random, that is normal control group, sham group, experimental group: 2h,4h,24h,5d,7d,15d,24d,30d group after injecting emboli, and 15d,24d,30d group are subdivided into MID group (n=8) and multiple infarct but not dementia group according to the Morris water maze.(二) Main agent10 % chloral hydrate; 4% Polyoxymethylene; c-fos agent; SABC kit; DAB kit.(三) Main instrumentationa set of microsurgery surgical instruments; operative procedure station; paraffin section machina; 37℃incubator; light microscope; water bath; Morris water maze.二,Methods(一)Make MID model by injecting emboli(二)The assessment standard of succeed model1,TTC staining2,Score learning and memory(三)Routine HE staining, observe ultramicrostructure of brain tissue by light microscope(四)Detect the expression of c-fos through immunohistochemistry.Results一,TTC stainingThe normal cerebral tissue is red, while spot or lamellar white infarct in experiment group rats can be seen.二,Learning and memory ability resultThe acquisition period in the normal group,sham group and MID group have different trend. The score in MID group lags the score in normal group and sham group, P<0.05, The frequency through location putting platform in MID group rats is low compared with the normal group and sham group rats. 三,HE stainingThe encephalic tissue cortical cells have normal form and structure in normal group. Neuron necrosis, gumnosis, pyramidal cell damage, gumnosis, neuron decrease, lay in disorder, the peripheral diastema of cell widen, a lot of neurons become necrosis, cytoplast swelling, cytoplasm staining blandly, karyolast dissolve and structure not clear in cortex, infracortical medulla and basal ganglia region, and have many contract neurons in infarct peripheral region of dementia group.Immunohistochemistry stainingThe average optical density value of c-los positive cells in normal rats is low, and increase a little in sham group, P＞0.05; The average optical density value of c-fos positive cells increase in cerebral cortex and hippocampus after cerebral multiple infarct 2h, but this is no different, P＞0.05; The average optical density value of c-fos positive cells increase after cerebral multiple infarct 4h, there is significant different compared with the normal control group and the sham group, P＜0.05. Lasting the ischemic time, the average optical density value of c-fos positive cells arrive to the peak after 24 hours, keep on 1 month. But the average optical density value of c-fos positive cells in the multiple infarct non-dementia group compared with MID group, there is no different (P＞0.05).DiscussionIn normal, c-fos involve in cell growth,cell differentiation,information transfer,neural plasticity and learning and memory and so on, but in pathobioloical condition, the expression and regulation of c-fos connect with the occurrence and devolpment of more diseases. Eugeniusz Nikolaev et al found c-fos mRNA increase in long-term memory process during initiative avoidance conditioned reflex. Wolfgang Tischmeyer et al and Anokhin K.V et al also found c-fos mRNA increase during learning and memory. Li Zhilin also found Fos proteinum increase during passive avoidance conditioned reflex. More and more literature report the expression of c-fos increase during learning and memory, especially long-term learning.Our study show that the expression of c-fos positive cell in the normal group and the sham group, there is no different. C-fos positive cells increase in cerebral cortex and hippocampus after cerebral multiple infarct 2h, but this is no difference. The expression of c-fos increase after cerebral multiple infarct 4h, there is significant difference compared with the normal control group and the sham group. Lasting the ischemic time, the expression of c-fos arrive to the peak after 24 hours, keep on 1 month. Which suggest c-fos may take part in the process of development of cerebral multiple infarct and MID, and the protect action for neuron in this process. But the expression of c-los in the multiple infarct non-dementia group compared with MID group, there is no difference. Which suggest c-fos may take part in patho-physiological process of cerebral multiple infarct and multiple infarct dementia; may only take part in patho-physiological process of cerebral multiple infarct, not take part in patho-physiological process of MID. May be the example less in the cerebral multiple infarct group.Conclusions1,Prepare multiple infarct and MID model by injecting emboli, and to certify model succeed by TTC staining,HE staining and Morris water maze.2, The expression of c-fos increased in rats brain after cerebral multiple infarct and multi-infarct dementia, suggesting c-los may be take part in patho-physiological process of cerebral multiple infarct and multiple infarct dementia. 3,The expression of c-fos in cerebral cortex and hippocampus after cerebral multiple infarct and multiple infarct dementia in rats, which are the important encephalic region about learning and memory increase, which suggest c-fos may be the foundation of the formation of learning and memory.