| Background: Epilepsy is the second nervous system disease next tocerebrovascular disease in all nervous system diseases. A total of25%ofdrug-refractory epilepsy require surgical treatment.Focal cortical dysplasia(FCD) is caused by about75%of children epilepsy and about25%adultepilepsy in epileptic patients who by surgical treatment. FCD is consideredthat it is caused by, in the formation process of the cerebral cortex, neuronsproliferation, migration, cortex formation etc normal procedure is subjected tothe disruption. International League Against Epilepsy make the latestclassification about FCD in2011. It think that early postnatal acquireddamages, including trauma, inflammation, and ischemic damage etc can causeFCD, called FCDⅢd type.Gap junction (GJ) is constituted by mutually corresponding half-channelon the cell membranes of two adjacent cells.Adjacent cell cytoplasm isconnected by the middle to take a small docking connectivity. At present, Gapjunction is a channel that between adjacent cells only the direct exchange ofmatter and information by. The channel is a non-selective ion channel, that canonly be permissible diameter of less than1.5nm or a molecular weight of lessthan1200daltons molecular substances and current through between thechannel.It can promote electrochemical coupling and metabolism betweencells. Connexin (CX) is a large class of membrane protein encoded by amultigene family. CX is highly conservative between mammalian species. CXamino acid sequence are highly homologous between rats and human.9aminoacids is only different between382amino acids, up to97%homology. Up tonow,15species Connexin are found in human and mammalian. CX43is themost widely distributed in brain.The seizures are a large number of neurons ultra synchronized discharge due to cell the homeostasis damage performance, or cell excitatory orinhibitory imbalance caused. Ion produced by electrical activity betweenneurons and plays an essential role in convulsions, the connexin consideredstructural basis of electrical synapses between neurons. Therefore, through thegap junction protein prompted adjacent cells to form a synchronizationactivities, resulting in the discharge of abnormal spread, there may be thestructural basis of the formation of the epilepsy.Very superficial understanding of the pathogenesis of FCD, on more theFCD domestic and international clinical research, mostly concentrated in theretrospective study of surgical specimens, but more the lack of basicexperimental study of the formation mechanism of FCD and epileptogenicthemechanism is unclear, the lack of a reliable animal model. Correctly establishFCD animal models of human disease etiology and pathogenesis of analysis,diagnostic methods to explore, targeted treatment and prognosis ofimmeasurable significance.As such, the present study intends to explore the feasibility of productionof animal models of FCDⅢd frozen in liquid nitrogen, and and CX43expression analysis.Objective: Application the method of liquid nitrogen refrigeration toestablish the FCD Ⅲd epilepsy rat model and verify, analyze the expressionof CX43in model,thus provide theoretical and experimental evidence tofurther explore the human FCD mechanism and future treatment.Methods: Take pregnant rats first day postpartum suckling mice asexperimental subjects, and frozen in liquid nitrogen neonatal rat cerebralcortex, are randomly divided into the experimental group and the controlgroup. The experimental group, based on the freezing time, are divided into30seconds,60seconds and90seconds three experimental subgroups. From21days to eight weeks after modeling are the experiment time, during this timeobserved the state of consciousness and behavior of the experimental animals.Monitor interictal EEG at the eight week of the experiment, perform skullMRI examination for experimental animals when at least eight weeks, perform HE staining and immunohistochemical staining, observe cell morphology andexpression of CX43. The final experimental data is analysed by SPSS13.0statistical software.Results: Spontaneous epileptic behavior are only observed five times inbehavior, showed only trembling like wet dog, twitching of facial muscles,increased chewing movements; rhythmic nod, action increased like washingface; most serious manifestation is forelimb clonus. Experimental group EEGepileptiform discharge rate is about41.6%in the average, and there is nostatistical difference between the experimental groups. The MRI positiveresults of the experimental group is manifested as long T1, T2signal atmodeling parts. HE staining of the brain tissue of the experimental group, seeexisting the layered structure and existing columnar structural disorder,existing abnormal morphological neurons and balloon cells, FCDⅢd-positiverate is about75%on average. The positive rate of the60seconds and90seconds experimental groups is significantly higher than the30secondsexperimental group(P <0.05), but the comparison between the60secondsexperimental group and the90seconds experimental group show nostatistically significant difference. The number of CX43positive cells per field(in mean±standard deviation are used): control group is the19.90±3.221,30seconds experimental group is45.24±3.185,60seconds experimental group is46.15±3.299,90seconds experimental group is46.66±3.230. The number ofpositive cells in the each experimental group increases significantly comparedwith the control group(P<0.05). There is statistically significant difference.Conclusion: Frozen in liquid nitrogen method can successfully establishFCDⅢd animal model, can partly simulate human FCDⅢd, the expression ofconnexin43enhance in rats of FCDⅢd. |
PDF Full Text Request