Abstract:

Objective To discuss the ameliorative effect of a novel antiepileptic drug Q808 on neuronal injury in temporal lobe epilepsy （TLE） rats， and to clarify its mechanism of action. Methods TLE rat model was prepared by intraperitoneal injection of the innovative antiepileptic drug candidate 6-（4-chlorophenoxy）- tetrazolo^{（5，1-a）} phthalazine （Q808）. Forty-five successfully modeled rats were randomly divided into model group， low dose of Q808 group， and high dose of Q808 group， and there were 15 rats in each group. The rats in low dose of Q808 group and high dose of Q808 group were gavaged with 20 and 80 mg·kg^-1 Q808，respectively， and the rats in model group were gavaged with an equal amount of 0.3% sodium carboxymethyl cellulose. Another 15 healthy SD rats were selected as control group. After 4 weeks of continuous gavage treatment， the morphology of the rats in varioius groups was observed； PONEMAH 6.X experimental animal telemetry platform was used to record the electroencephalogram of the rats in various groups； Golgi staining was used to observe the morphology of dendritic and dendritic spine density of hippocampal CA1 neurons of the rats in various groups； Western blotting method was used to detect the expression levels of synaptic plasticity-specific protein calcium/calmodulin-dependent protein kinaseⅡ （CaMKⅡ） in hippocampus tissue of the rats in various groups. Results The rats in control group showed normal activity without convulsions or other abnormal manifestations. The rats in model group， low dose of Q808 group， and high dose of Q808 group showed varying degrees of reduced activity， trembling and nodding， loss of balance， muscle rigidity and forelimb convulsions， gradually transforming into whole-body muscle rigidity and standing， followed by falling backwards， and there were no convulsions during the interictal period. Compared with control group， the total durations of epileptic seizures of the rats in model group， low dose of Q808 group， and high dose of Q808 group were significantly prolonged （P<0.01）. Compared with model group， the total durations of epileptic seizures in low dose of Q808 group and high dose of Q808 group were significantly shortened （P<0.01）. The hippocampal CA1 neurons of the rats in control group showed regular distribution of dendrites with dense and orderly dendritic networks. The hippocampal CA1 neurons of the rats in model group showed disordered arrangement of dendrites with massive dendritic entanglement， forming thicker nerve fiber bundles. Compared with model group， the dendritic networks of hippocampal CA1 neurons of the rats in low dose of Q808 group and high dose of Q808 group were partially recovered with relatively regular arrangement. Compared with control group， the dendritic spine density of hippocampal CA1 neurons of the rats in model group was significantly decreased （P<0.01）. Compared with model group， the dendritic spine densities of hippocampal CA1 neurons in low dose of Q808 group and high dose of Q808 group significantly increased （P<0.01）. Compared with control group， the expression levels of CaMKⅡ protein in hippocampus tissue of the rats in model group， low dose of Q808 group， and high dose of Q808 group were significantly decreased （P<0.01）. Compared with model group， the expression levels of CaMKⅡ protein in hippocampus tissue of the rats in low dose of Q808 group and high dose of Q808 group were significantly increased （P<0.01）. Conclusion The novel antiepileptic drug Q808 has an ameliorating effect on the TLE model rats；its mechanism may be related to Q808’s ability to reduce the dendritic lesions in hippocampal CA1 neurons and increase the expression level of synaptic plasticity-related protein CaMKⅡ protein.

Key words: Temporal lobe epilepsy, 6-（4-chlorophenoxy）-tetrazolio^{（5，1-a）} phthalazine, Synaptic plasticity, Calcium/calmodulin-dependent protein kinaseⅡ, Long-term potentiation