Expression Research Of Pumilio-2 In Pilocarpine-Induced Epilepsy Model Rats And Patients With Intractable Epilepsy

Objective To investigate the expression pattern of Pumilio2 (Pum2) in drug-refractory temporal lobe epilepsy (TLE) patients and lithium chloride-pilocarpine-induced epilepsy model rats for exploring the possible role of Pum2 in epileptogenesis.Methods1.20 surgical specimens were collected from patients with intractable epilepsy, and 20 temporal neocortex samples were obtained from patients who underwent required surgery for severe head trauma for comparision.2. Adult male Sprague-Dawley rats were induced to establish lithium chloride-pilocarpine-induced rat model of epilepsy. Based on the epilepsy development stages, the rats were randomly divided into seven groups, including a control group and six TLE groups:rats were sacrificed at 1 d, 3 d,7 d,14 d,30 d, and 60 d after the onset of status epilepticus (SE).3. Real-time quantitative PCR (qRT-PCR) was utilized to determine the expression level of miR-134, Pum2 and Nav1.6 mRNAs. Western blot and immunohistochemistry were used to verify the Pum2 protein expression level further. Double-labeled immunofluorescence was performed to detect the distribution of Pum2 in neurons. And Golgi staining was used to detect the dendritic morphology of neurons.Results1. miR-134 was up-regulated in epileptic rats. Except for 7d and 14d post-seizure, miR-134 expressed at 1 d,3 d,30 d, and 60 d after SE was elevated significantly compared to the control group (p< 0.05)2.The expression of Pum2 was significantly reduced in brain tissues from TLE patients in comparison to controls (P<0.05)3. The expression level of Pum2 was decreased in epileptic rats. qRT-PCR and Western blot analysis showed that Pum2 expression in epileptic rats was significantly different than control At each time point after SE(P<0.05). Immunohistochemistry showed that Pum2 expression remained at a low level at 3 d,7 d,14 d,30 d, and 60 d post-seizure (P <0.05), and it was downregulated 1 day after seizure relative to control, but this difference was not statistically different(p>0.05).4. Pum2 was expressed in the cell bodies and dendrites of neurons but did not co-localize with astrocytes or nuclei.5. the dendritic branch and length of neurons in hippocampus was significantly increased in pilocarpine-induced epileptic rats when compared with the control groups (p< 0.05)6. The expression level of Nav1.6 mRNA was up-regulated in epilepsy model rats. And the differences between epileptic rats at each time point, except Id, post-seizure and controls were statistically significant(p<0.05).ConclusionsPum2 expression was less in TLE patients and a rat model of epilepsy, suggesting that decreased expression of Pum2 may be involved in the occurrence and pathogenesis of TLE.