Effect of nectin-1 expression after being inhibited by lentivirus on epileptogenesis and mossy fiber sprouting

Xiaofang WU; Yunli YU; Zhanhui FENG; Xiaoping LI; Shulei HUANG

ABSTRACT

Objective:

To explore the effect of adhesion molecule nectin-1 expression on epileptic seizure and mossy fiber sprouting.

Methods:

(1) Adult male SD rats were randomly divided into control group ( n=6), empty vector group ( n=6) and lentivirus interfered group ( n=24), and rats in the lentivirus interfered group were further divided into 4 subgroups ( n=6) according to the time points of lentivirus injection (3, 7, 14 and 30 d after injection). The protein expression of nectin-1 in the hippocampus of rats was detected by Western blotting. (2) Another 12 male SD rats were randomly selected and divided into lentivirus epilepsy group ( n=6) and empty vector epilepsy group ( n=6). Lentivirus and empty lentivirus vector were injected into the hippocampus of the above two groups respectively, and then, pilocarpine epilepsy models were kindled; the behavior changes of these rats were recorded, and changes of mossy fiber sprouting in the hippocampus were observed by Timm staining.

Results:

(1) There were significant differences in hippocampal nectin-1 protein expressions in each group ( F=76.120, P=0.000); the nectin-1 expression in the 7, 14, and 30 d subgroups was significantly decreased as compared with that in the control group and empty vector group ( P<0.05). (2) The results of behavior changes showed that the times required for the lentivirus epilepsy group to be kindled successfully ([34.33±2.38] min) were significantly longer than those for the empty vector epilepsy group ([24.50±2.06] min, t=7.650, P=0.000). In terms of seizure level, the seizure level of rats in the lentivirus epilepsy group was significantly lower at each time point within one h modeling than that of rats in the empty vector epilepsy group ( P<0.05). After kindling, the time of spontaneous seizure appeared in the lentivirus epilepsy group was significantly longer than that in the empty vector epilepsy group, and the frequencies of spontaneous seizure in the lentivirus epilepsy group were significantly decreased as compared with those in the empty vector epilepsy group ( P<0.05). Timm staining scores in the lentivirus epilepsy group (3.500±0.224) were significantly lower than those in the empty vector epilepsy group (4.667±0.211, t=9.289, P=0.000).

Conclusion:

Inhibition of nectin-1 expression in hippocampal area of epileptic rats can delay the occurrence of epilepsy and reduce the frequencies of spontaneous seizures of epileptic rats, whose mechanism may be related to the reduction of nectin-1 in the formation of mossy fiber sprouting in abnormal neural circuits of hippocampal area.