Study On The Different Mechanism Of Neuron Injury

Causes of injury of CNS include trauma, ischemia, hypoxia, intoxication,which makes an eventful effect to people. once it happens which leds to greatconfusion,range from a abnormal life to death,lose quality of your life,couldcause serious economic and social harm.With social modernization,this kind ofinjury cames in increasing numbers.So it is a hot research field,but thestructures and mechanism of CNS is a bit complicated,So far is unknown. CNSresulted in following three kinds of injury:damage induced by oxidative stress,degenerative disorder of the central nervous system,excitatory amino acid(EAA) an important neurotransmitter is released.SHSY5Y neuroblastoma cells are used for the research of neuron injureand its mechanisms.We establish the injury model on different mechanism anduse SHSY5Y cell line: damage induced by glucose-glucose oxidase reactionleads to oxidative stress,glutamic acid solution leads to excitatory amino acidintoxation,6-OHDA leads to neurodegenerative diseases.We research for calcium channel,membrane potentiala,apoptosis andnecrosis first. The results showed that model were established successfully andwhich depended on its concentration and the culture-duration.We foundalthough mechanism is entirely different, calcium channel,membrane poten-tiala,apoptosis and necrosis are all changed compared with the controls: theconcentrations of calcium ion intra-cellular is higher and membrane potentialais degraded progressively along with the severity of injury, and were related toinjury time and happened at the same time. Among the total, after leastconcentration glutamate and6OH-DA were given and lasted for certain period,the concentration of calcium ion in the cells is degrade and membrane potentiala is heighten on the contrary, This elucidate that debita spissitudineglutamate and6OHDA lasted for certain period have neuron protection,oxidative stress injury has no this protection phenomenon. Meanwhile, neuroncells will be dead with high dose glutamate and6OH-DA for long time,butoxidative stress for short time induce neuron cells death, to explain neuron cellshas a poor tolerance against hypoxia.In this kinds of injury,glutamate is themost obvious one which leads to higher intracellular Ca2+.at the highestconcentration there is no significant difference of membrane potential.Moreover, there is a positive predictive value of glutamate, when concentrationare higher than that numerical value, the cell damage become more serious,this needs further investigation.The MTT was assayed for the activity of cell. Adefinite goal to point of injury time and concentration,we done the detection ofapoptosis and necrosis,we found that molecular mechanism of neuron celldeath induced by glutamate included both apoptosis and necrosis,lowerconcentration GLU induced early apoptosis; higher concentration GLU inducednecrosis. Then this early apoptosis practice have exist from GLU inducedneuron cell dead. Kill neuron cells to necrosis mainly by6OHDA, There washardly early apoptosis, furthermore the cell number is in a dose-and timedependent manner;and there is significant difference of early apoptosis in theoxidative stress injury, but there is no significant difference of necrosis,thisshows conclusion apoptosis, injury mechanisms induced by oxidative stressinjury.So we done the experimental research on signal transduction mechanismchange. At the present stage, receptor interaction proteinum (RIP)1and3iswell known of mechanism programmed cell necrosis, It is universallyacknowledged that the two proteins are the key regulatory proteins, theirinteractions leads to programmed cell death. We found that RIP1protein hadthe significantly increased.so necrosis hold a leading post.we determine variation of RIP1and RIP3when neuron is injury. On the basis of westerndetection,we found in GLU and DA models following neuron injury, the RIP1become more higher as the damage of neuron. No obvious changes could befound with RIP1；but in GOD models following neuron injury, No obviouschanges could be found with RIP1and RIP3.So that we may conclude that:among three different types of neuron injury,they are complete accordance characterized by high calcium concentrationswithin a cell to follow cell membrane potential depress；debita spissitudineGLU and6-OHDA have protection in the necessarily action time. It includesboth apoptosis and necrosis of the neuron injury by GLU,it leads to apoptosiswhen it is low concentrations; and necrosis hold a leading post when the neuroninjury by6-OHDA；apoptosis hold a leading post when damage induced byoxidative stress, This shows neuron cell has a poor tolerance ag ainst oxidativestress, and the key regulatory proteinum of necrosis-RIP1/RIP3have nomarked change, this consistent with apoptosis hold a leading post when damageinduced by oxidative stress； the concentration of the key regulatory proteinumof necrosis-RIP1was higher, but the other key RIP3protein level has nochange, These results suggest that:①So far it has not heard of RIP1and RIP3detection of neuron injury, the particularity of neuron cell result in differentfunction, so RIP1mediates other passageway;②result display low level ofRIP3, to consider that RIP1mediates other passageway and RIP3to change(such as phosphorylation)；③Possiblly there is another passageway of necrosis,in this way,RIP1has determinateaction, it is important and sensitive part oflead action or secondary part, and RIP3don't engage this event.