Effect of microinjection of tyrosine kinase receptor binding protein B3 agonist into hippocampus on spontaneous seizures in epileptic model rats and its mechanisms / 中华行为医学与脑科学杂志

ABSTRACT

Objective:To investigate the effects of hippocampal injection of tyrosine kinase receptor binding protein B3(Ephrin-B3) agonist on spontaneous seizures and the expression of hippocampal secretory glycoprotein (Reelin) and phosphorylated adaptor protein (p-Dab1) in epileptic model rats.Methods:Seventy-eight rats were randomly divided into control group and model group according to body mass matching with 39 rats in each group.The rats in control group were fed normaly, and the rats in model group were established epilepsy model by intraperitoneal injection of lithium chloride pilocarpine. The hippocampal tissues were taken in the acute phase (7 days), quiescent phase (14 days) and chronic phase (60 days) after the successful induction of status epilepticus. The levels of Reelin protein and p-Dab1 protein in the hippocampal tissues of epileptic model rats and normal rats were detected by immunohistochemistry and Western blot.And thirteen rats were randomly selected at each time point. Another 48 rats were randomly divided into normal Fc-control group, normal EphB3-Fc group, epilepsy Fc-control group and epilepsy EphB3-Fc group, with 12 rats in each group. Rats in the first two groups were fed normally, and those in the latter two groups were established epileptic model. Seven days after modeling, all rats were injected into bilateral hippocampus with EphB3-Fc (Ephrin-B3 agonist) and FC control (control agent of Ephrin-B3 agonist) according to the grouping, once a day for 7 days. After administration, the changes of behavior and EEG were observed within two weeks. At the same time, the expression of Reelin protein and p-Dab1 protein were detected by immunohistochemistry and Western blot. SPSS 21.0 was used for statistical analysis, One-way ANOVA was used for multi group comparison, and Tukey's test was used for pairwise comparison.Results:The results of immunohistochemistry and Western blot showed that compared with the control group, the levels of Reelin and p-Dab1 protein in hippocampus of model group decreased significantly at 7, 14 and 60 days after epilepsy (all P<0.01). The results of immunohistochemistry showed that compared with epilepsy Fc-control group, the levels of p-Dab1 ((0.41±0.04), (0.58±0.06), P<0.05) in epilepsy EphB3-Fc group increased significantly.Western blot result showed that the level of p-Dab1 in epilepsy EphB3-Fc group increased compared with that of epilepsy Fc-control group (1.34±0.04), (2.26±0.10), P<0.01). Compared with epilepsy Fc-control group, epilepsy EphB3-Fc group showed less average seizure duration ((39.00±1.79)s, (26.50±1.87)s; t=23.21, P<0.01), less frequencies ((2.00±0.89), (0.50±0.55); t=2.32, P<0.01) and less latent period ((6.33±1.37)day, (12.50±1.87)day; t=2.52, P<0.01) in spontaneous recurrent seizures. Compared with epilepsy Fc-control group, epilepsy EphB3-Fc group showed lower average amplitude ((37.30±1.21)μV, (29.00±1.41)μV; t=25.14, P<0.01), less average seizure duration ((5.35±0.19)s, (2.35±0.19)s; t=3.13, P<0.01). Conclusion:Ephrin-B3 alleviated spontaneous recurrent seizures by upregulating Reelin and p-Dab1 in temporal lobe epilepsy rat.