The Expression Of P-mTOR, P-S6K1and P-4EBP1in The Human Brain With Refractory Epilepsy

Background：The pathogenesis of epilepsy research focused on membrane proteins whichregulate excitatory neuron, but now more attention has drawn to intracellular proteinsand their interrelated action. mTOR singling pathway including growth factors,insulin, nutrients, amino acids, glucose, can response to the extracellular stimulus,which plays an important role on a many physiological process including cell growthand cell cycle by up regulating PI3K/Akt and down-regulating4EBP1, S6K1pathway.So it is meaningful to understand the role and regulation mechanisms of the mTORsignaling pathway in refractory epilepsy.Objective：To observe the expressions of p-mTOR, p-S6K1and p-4EBP1in the human brainwith refractory epilepsy and to explore the role of mTOR signaling pathway inintractable epilepsy.Materials and methods：Collecting the brain tissue of24patients with refractory epilepsy for surgicaltreatment from March2010to July2011as experimental group in hospitalizedEpilepsy Center at the First Hospital of Jilin University, Changchun City. Collectingtemporal lobe or frontal lobe brain tissue from6autopsy of unnatural death during thesame period.Using immunohistochemistry to observe the expression of p-mTOR, p-S6K1, p-4EBP1in the two groups of brain tissue, and analyzed statistically.Results：(1）p-mTOR, p-S6K1and p-4EBP1are expressed in both experimental andcontrol groups. The numbers of positive cells of p-mTOR, p-S6K1and p-4EBP1expression were38.33±3.30,38.14±3.10,38.00±2.86in brain tissues in the casegroup. While in control group, the numbers of positive cells were9.60±0.55,8.37±0.32,8.80±0.47respectively. There are significant differences between the caseand control group(P＜0.01). The expression level of p-mTOR, p-S6K1, p-4EBP1in the brain tissue of patients with different seizure frequency and with differentduration：the number of positive cells of p-mTOR, p-S6K1, p-4EBP1in the group ofseizure fewer than10attacks per month are35.60±0.55,35.33±0.21,35.60±0.39.Thenumber of positive cells in the group of seizure10times and more than10times permonth are41.05±2.50,40.95±1.69,40.40±2.09. The level of positive cells in thegroup of10times and more than10times per month was significantly higher than thegroup of seizure fewer than10attacks per month. The difference was significant (P<0.05).The number of positive cells in the group of fewer than10years are35.88±0.80,36.00±1.60,35.89±0.83.The number of positive cells in the group of10years and more than10years are42.40±0.55,41.71±0.47,41.51±0.28。 Theexpression level of p-mTOR, p-S6K1, p-4EBP1in the brain tissue of patients in thegroup of epilepsy10years and more than10years was significantly higher than thegroup of epilepsy fewer than10years and the difference statistically significant (P<0.05).(2)The structural changes of brain tissue were observed under the opticalmicroscope and electron microscope. Under the optical microscope: the distribution ofnerve cells were uneven, the nucleus was vacuolated, the cytoplasm was less andGliosis. Under the transmission electron microscope the number of neurons wasreduced, nuclear condensation, the heterochromatin was increased, the nucleolus weredissymmetry and the nuclear membrane was breakage, also see neurons becamepsychotic, cell body became smaller, astrocyte cell membrane became edema,chromatin was dissymmetry, some mitochondrial were swelling and transparent, andothers were vacuolated, the mitochondrial crista was in disorder.（3）p-mTOR, p-S6K1and p-4EBP1are expressed in vascular parts in bothexperimental and control groups.In the experimental group, the expression is highconcentration.In the control group, the expression is scattered in a small amount.Conclusion:1. p-mTOR, p-S6K1and p-4EBP1are widely expressed in neurons andglialcells with refractory epilepsy, which was significantly increased compared withcontrol group. The expression of p-mTOR, p-S6K1and p-4EBP1is related tofrequency of epileptic seizures and course.2. The signaling pathway of mTOR may be involved in the pathophysiological process after the seizure.3. The signaling pathway of mTOR may be correlated with angiogenesis andvascular proliferation.Innovation points:p-mTOR, p-S6K1, p-4EBP1in the human brain with intractable epilepsy wasfirst studied, to our knowledge, it has not been reported at home and abroad.