TAT-GluA2CT interferes with the protective effect of GluA2/TARPγ-8 coupling on nerve injury in status epilepticus model of rats / 中华实用儿科临床杂志

ABSTRACT

Objective:To investigate the protective effect of interfering peptide TAT-GluA2CT on hippocampal neurons in the Lithium chlorine-Pilocarpine status epilepticus model and the optimal time of administration.Methods:Male SD rats (72 cases) were induced to status epilepticus by using Lithium chlorine-Pilocarpine, while a control group ( n=12) was established.The 72 rats were divided into epilepsy group ( n=12), TAT-sham peptide group ( n=12), TAT-GluA2CT peptide group ( n=48) according to the random number table method, and the TAT-GluA2CT peptide group were further divided into the pre-1 h group ( n=12), the post-2 h group ( n=12), the post-4 h group( n=12), and the post-6 h group ( n=12) according to the administration time of the TAT-GluA2CT peptide.Nissl staining and terminal dUTP nick end labeling (TUNEL) assay were performed on 6 rats each from control group, epilepsy group, TAT-shampeptide group, pre-1 h group, post-2 h group, post-4 h group, and post-6 h group to observe the morphological changes and apoptosis of neurons in the CA1 region of the rat hippocampus.Western blot and co-immunopercipitation test were used to detect the expression of GluA2[second subunit of α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) recepter] and the coupling of GluA2/transmembrane AMPA receptor regulatory protein (TARP γ-8) complex in control group, epilepsy group, pre-1 h group, post-2 h group, post-4 h group and post-6 h group.The t-test was used to compare the data differences between 2 groups, and one-way ANOVA was adopted to compare the differences between the groups. Results:Compared with the epilepsy group, the number of neurons in each TAT-GluA2CT peptide group increased significantly, and the difference was statistically significant( epilepsy group 20.07±3.51, pre-1 h group 39.40±2.39, post-2 h group 38.43±2.42, post-4 h group 30.30±2.55, and post-6 h group 27.93±3.20, F=235.28, P<0.05). Compared with the epilepsy group, the number of apoptotic cells in each TAT-GluA2CT peptide group was significantly reduced, and the difference was statistically significant(epilepsy group 31.47±3.19, pre-1 h group 7.30±3.45, post-2 h group 9.27±3.81, post-4 h group 12.86±3.08, and post-6 h group 14.43±3.13, F=248.60, P<0.05). Compared with the control group, the expression of hippocampal GluA2 decreased after epilepsy induction, and the difference was statistically significant(control group 21 626.53±2 700.58, epilepsy group 14 578.16±2 917.02, pre-1 h group 13 375.47±3 180.54, post-2 h group 15 244.10±1 390.41, post-4 h group 15 799.16±4 559.49, post-6 h group 15 722.95±1 756.01, F=3.83, P<0.05). No statistical difference was observed in the expression of GluA2 between the TAT-GluA2CT peptide group and the epilepsy group( F=0.45, P=0.77). Compared with the epilepsy group, GluA2/TARPγ-8 complex coupling was decreased in each TAT-GluA2CT peptide group, and the difference was statistically significant(epilepsy group 24 509.80±3 718.54, pre-1 h group 12 055.18±5 847.11, post-2 h group 9 630.51±5 805.17, post-4 h group 12 749.35±7 108.45, post-6 h group 11 092.98±7 330.08, F=10.68, P<0.05). Compared with the epilepsy group, the incubation period of seizures in the pre-1 h group was prolonged and the seizure rating was decreased, with statistically significant differences[epilepsy group (18.58±3.99) min, pre-1 h group (103.25±9.21) min, t=29.23, P<0.05]. Conclusions:TAT-GluA2CT peptide can attenuate the neuronal damage in hippocampus of epileptic rats.The neuroprotective effect of TAT-GluA2CT peptide was most obvious at 1 h before or 2 h after administration of Pilocarpine.