The Relationship Among IL-2,IL-2R And Epileptogenesis

Epilepsy is a kind of central neurous system diseases, badly endangering the health of human being. Many researches have showed that the failed modulation in the neuro-immuno-endocrine network is involved in the epileptogenesis, in which the neural mechanism is main, while the immune and the endocrine factors take part in the mechanism by modulating receptors, intracellular messages or gene. As a kind of cytokines, interleukin-2(Il-2) not only plays an important role in the immune response and inflammatory reactions, but also modulates the functions and activities of central nervous system. Our lab has observed that Il-2 could induce epileptic seizure. The expression of IL-2R was increased in brain of rats with seizure induced by Coriari Lactone (CL). But the reports about the relationship among IL-2, IL-2R and epileptogenesis are seldom seen. Nitric oxide synthase (NOS) is an enzyme of nitric oxide which is an important messenger in the body. In central neural system, the NOS is widespread normally and the expression of NOS will be increased in the brain of epileptic animals. It was all known that Glutamate(Glu) is a representative excitory neurotransmitter and is seen increased in brain of animals with epilepsy. As astrocytes are the most aboundent in the central neural system, the relationship between astrocytes and epilepsy are concerned. In order to investigate the relationship among IL-2,IL-2R and epileptogenesis, the changes of NOS,Glu and IL-2R expression in rats with seizures induced by IL-2 following the pretreatment of immunosuppressants were studied by means of Western blot, immunohistochemistry, cell culture and electroencephalogram(EEG).And we observed the effects of ACM on the changes of the expression of Glu and IL-2R in rats by the means mentioned above.First part of this dissertation is to investigate the mechanism of Il-2 inducing epilepsy , the anti-epileptic effect of immunosuppressants on rats with seizure induced by IL-2 and its mechanism, the changes of behavior ,EEG, Glu and IL-2R of cerebral cortex and hippocampal were investigated by EEG and immunohistochemical staining after injecting the drugs. The rats were randomly divided into four groups: Group A ,normal saline control group; Group B: IL-2 group, injected with IL-2(2500U/kg) intracerebroventricularly (i.c.v); Group C: Cyclosporine(CsA)+Il-2 group, pre-injected with CsA (10mg/kg/d) into abdomen,14 days later injected with IL-2(2500U/kg); Group D: Glucocorticoids(GC )group, injected with Dexamethasone(Dex)(4mg /kg) into abdomen. The results showed : Group A , the rats appeared no behavior changed; hippocampal and cerebral EEG of this group showed no sharp waves , spike and waves complexes; immunohistochemical results of this group showed that there wre many immunoreactive(IR) positive cells of Glu,IL-2R in cerebral cortex and hippocampal. Group B , the rats showed epileptic activities ,about III～IV grade; EEG showed typical burst pattern discharge, such as sharp waves, spike and waves complexes ; the results of immunohistochemical staining showed that the IR positive cells of Glu,IL-2R in cerebral cortex and hippocampal of Group B were significantly increased compared with Group A, (P<0.05). Group C , seizure was partly restrained in rats,just about I grade ;and the EEG showed only 2～3low spike and waves complexes; the results of immunohistochemical staining showed that the IR positive cells of Glu,IL-2R in cerebral cortex and hippocampal of this group were significantly decreased compared with Group B, (P<0.05). Group D, the rats showed no epileptic activities, there was no typical epileptic waves in EEG; the IR positive cells of Glu,IL-2R in cerebral cortex and hippocampal were decreased ,compared with group A ,and it has significant difference between group D and group A, (P<0.05). The study suggested that IL-2 could induce the epileptic seizure. While immunosuppressants could restrain the seizure, of which mechanism might be related to restraining the expression of Glu and IL-2R.The second part is to study the relationship between seizure induced by IL-2 and NOS in cerebral cortex, which is a synthetase of NO. And the content of NOS can reflect that of NO. We examined the variations of behavior and NOS expression in rats with seizures induced by IL-2 and with seizures induced by IL-2 following the pretreatment of immunosuppressants by means of Western blot and computer-assisted image analysis. The rats were randomly divided into four groups: A ,normal saline control group; Group B, IL-2 group, injected with IL-2(2500U/kg) intracerebroventricularly (i.c.v); Group C, Cyclosporine(CsA)+Il-2 group, pre-injected with CsA (10mg/kg/d) into abdomen,14 days later injected with IL-2(2500U/kg); Group D, Glucocorticoids(GC)group, injected with Dexamethasone(Dex)(4mg /kg) into abdomen. The results demonstrated that :(1) Seizure developed after injecting IL-2 into the lateral ventricle of rats, and the expression of NOS in the cerebral cortex was significantly higher than that of the normal saline control group(P<0.05), (2)seizure was restrained and the expression of NOS in the cerebral cortex was decreased significantly in the CsA+Il-2 group (P<0.05) compared with the IL-2 group, and (3)the rats were in a suppressive state in the GC group and the expression of NOS in the cerebral cortex was greatly decreased, compared with the normal saline control group,(P<0.05). These data suggest that IL-2 could induce seizure and promote the expression of NOS. Immunosuppressants could have the function of restraining the seizure and significantly reduce the expression of NOS.The third part is to explore the role of activating astrocytic conditioned medium (ACM) in epileptogenesis and its effect on the expression of glu and Il-2R .The expression changes of Glu and IL-2R of hippocampus and cerebral cortex were investigated by immunohistochemical staining after injecting ACM (10ul) into the lateral ventricle of rats, and the behavior change were observed. The rats were devided into 2 groups at random: Group A :normal saline control group; Group B:ACM group, injected with ACM(10μl) intracerebroventricularly (i.c.v).The results showed : the rats showed epilept含ic seizure in group B (about III-IV grade) after injecting ACM(10ul) into the lateral ventricle of rats. The results of immunohistochemical staining showed that, at 2h after injecting ACM, the IR positive cells of Glu,IL-2R in hippocampus and cerebral cortex were significantly increased compared with the control group . And there was significant difference between the two groups, (P<0.05). The study suggested that ACM could induce the epileptic seizure, of wich mechanism might be related to increasing the expression of Glu and IL-2R.In conclusion , IL-2 can induce epileptic seizure. There was close relationship among IL-2 ,IL-2R and epileptogenesis. CsA could significantly reduce the expression of NOS and have the function of restraining the seizure by reducing production of IL-2 and IL-2R. GC could also reduce the expression of NOS and can restrain nervous excitability. ACM could induce the epileptic seizure and its mechanism might be related to increasing the expression of Glu and IL-2R.The study indicates that IL-2 and IL-2R can take part in epileptogenisis. CsA and GC have the role of restraining epilepsy.