The Interactions Of The Alterations Of The Periaqueductal Gray Structure And The Epileptogenesis

Objective We aimed to investigate the interactive relationships between the alterations of the ventrolateral Periaqueductal Gray(v PAG)structure and the epileptogenesis in a pilocarpine-induced epilepsy model.Methods90 achieved status epilepticus(SE)were randomly divided into 7 subgroups,Control,12 h,24 h,72 h,10 d,20 d and 30 d.15 control rats were injected with saline.5 rats per subgroup were used to perform double-label immunofluorescence assay,5 rats used to perform HE staining and TUNEL assay,and 5 rats used to perform western blot(WB)to analyze the levels of vesicular glutamate transporter 1(v GLUT1)and vesicular γ-amino butyric acid transporter(v GAT)in the v PAG area.Additionally,13 normal rats were selected to performe the stereotactic injection lesion to investigate that the influences of the v PAG networks impairment on spontaneous recurrent seizures(SRSs)via video monitoring for 2 weeks.All statistics were presented as mean ± standard error(M ±SEM)and statistical significance was set at P< 0.05.One-way analysis of variance(ANOVA)was applied to analyze the mean intensities of v GLUT1 and v GAT puncta,the mean number of TUNEL-positive cells and the normalized value of WB.Student’s test was applied to compare the differences in the seizures frequency,duration,and severity of SRSs between two groups.An obviously increased tendencies of the levels of v GLUT1 and v GAT and the neuronal damages were observed in the v PAG area in the first 72 h,a gradual recovery tendency appeared in the SRSs period but has not been recovering to the level of the control group up to 30 d.The mean intensities of v GLUT1 and v GAT puncta at 72 h was significantly increased than other groups(P< 0.01).The mean number of TUNEL-positive cells increased significantly in the Pilo-group compared to the control group(P< 0.01).The normalized value of v GLUT1 and v GAT at 72 h was significant more than the control group,12 h,20 d and 30 d(P< 0.01).The normalized value of v GLUT1 and v GAT at 24 h,72 h and 10 d were significantly higher than the control group(P< 0.01).Damaged neurons became shrunken,darken stained with the shape of spindle in HE staining.TUNEL-positive cells presented a compact nuclear condensation with the color of brownish yellow or nigger-brown.After 2 weeks video monitoring,seizures frequency,duration,and severity were significantly increased in the Pilo-group compared to the control group(P< 0.01).ResultsConclusions The results demonstrated that epileptogenesis would cause the alterations of function and structure of the v PAG,in addition,the destructions of the v PAG area would also deteriorate epileptogenensis.