Maternal Epileptic Seizure Induced By Pentylenetetrazol:the Expression Of Glycogen Synthase Kinase-3β In The Prenatal Rat Brain

Objective: It is estimated that one in200(0.5%) pregnantwomen hasepilepsy.The major threats to women with epilepsy are an increase inseizure frequence in about a third of women during pregnancy andmaternal complications,as are the fetus and particularly the fetal brain.Children of mothers with epilepsy have lower perinatal vitality rates(APGAR scores) and higher perinatal mortality rates than the generalpopulation. Different authors have observed a higher incidence ofintrauterine growth retardation in children of both mothers with epilepsytreated with AEDs and those not treated, suggesting a possible direct effectof maternal epilepsy on the fetus. However, the detailed mechanism andinfluences underlying epileptic disorders are still unrevealed. In our study,the female Sprague-Dawley(SD) rats were kindled by intraperitonealinjection of pentylenetetrazol(PTZ). Seizure was induced in pregnant ratusing intraperitoneal injection of pentylenetetrazol (PTZ)(35mg/kg for15days). After kindled the female rats were mated. At gestationaldays(GD)15.5, the prenatal rat brain were obtained. The expression ofGSK-3β,P-GSK-3β protein in the prenatal rat brain was determinedthrough the methods of Western Blot. The expression and distribution ofP-GSK-3β protein in the prenatal rat brain was determined through themethods of Immunohistochemistry.Methods: we establish chronic epileptic model inducing bypentylenetetrazol (PTZ) intraperitoneal injection.45female SD rats(7-8weeks, weight200±20g) were randomly divided into three groupsconsisting of15animals each, as are the epilepsy group (PTZ group),saline group (NS group) and the normal control group (NC group). Since the first day, animals in the PTZ group every day at9:00wereadministration by i.p. injections of35mg/kg PTZ, until kindled. Theanimals in the second group (the saline group) received an equivalentvolume of normal saline on similar schedule. The third group received notreatment. Immediately after injection,seizure activity was observed for45min and scored according to Racine, modified by Becker et al, as follows:stage0, no response; stage1, ear and facial twitching; stage2, myoclonicjerks without rearing; stage3, myoclonic jerks, rering; stage4, turn overinto side position, clonic-tonic seizures; stage5, turn over into sideposition, generalized clonic-tonic seizures. If we observed three timessuccessive seizures of grade4or5, the animals were considered to bekindled. After kindled the female rats were mated. Embryonic day0.5being the day in which positive vaginal plug was observed. The female ratwhich received PTZ injection(35mg/kg) i.p. from0.5-14.5days afterinsemination. In the NS group, the female rat received an equivalentvolume of0.9%saline solution injection on similar schedule. In the NCgroup, the pregnancy rat received no treatment. At gestationaldays(GD)15.5, all pregnancy rats were anesthetized by10%chloralhydrate, and the prenatal brains were obtained by caesarean section.The expression of GSK-3β and P-GSK-3β protein in the prenatal brainwas determined through the methods of Western Blot. The expression anddistribution of P-GSK-3β protein in the prenatal rat brain was determinedthrough the methods of Immunohistochemistry.Results:1Results of behavior: From sixth day to eighth day, thefemale rats in PTZ group began to nod,wash their face,and thesymptom gradually became seriouser,following by,myoclonic jerkswithout rearing; myoclonic jerks, rering; turn over into side position,clonic-tonic seizures; turn over into side position, generalized clonic-tonicseizures. Seizure was induced in pregnant rat using intraperitonealinjection of pentylenetetrazol (PTZ)(35mg/kg for15days). No seizureswere found in the normal group. 2Result of Western blot: The expression of P-GSK-3β protein in PTZgroup was increased obviously compared to NC group (P<0.05). Theexpression of P-GSK-3β protein in PTZ group was increased obviouslycompared to NS group (P<0.05). Comparisons of P-GSK-3β proteinbetween NC group and NS group were of no significant difference(P>0.05). The expression of GSK-3β protein among NC, NS and PTZgroups were no significant difference (P>0.05).3Result ofImmunohistochemistry: The p-GSK-3β immunohistoche-mical products were brown and most of them were in the endochylema ofthe neuron. And the p-GSK-3β is enriched in the cortex of the prenatalbrain. The number of immunopositive cells in PTZ group was increasedobviously compared to NC group(P<0.05), and compared to NS group(P<0.05). And in NC group and NS group, their was no significance(P>0.05).Conclusions:1Seizure was induced in pregnant rat usingintraperitoneal injection of pentylenetetrazol(35mg/kg).2The expression of P-GSK-3β protein in PTZ group was increasedobviously compared to NC group and NS group. In the cortex of theprenatal brain, the expression of P-GSK-3β protein in PTZ group wasincreased obviously compared to NC group and NS group.Seizures duringpregnancy may affect the development of the cortex of the prenatal brain,and p-GSK may plays a key role in the process.