The Effects Of Ginsenoside Rb1on The Apoptosis Of Neurons And Expressions Of β-catenin Protein In Hippocampus Of Epileptic Rats

Objectives: To investigate the effects of ginsenoside Rb1onthe apoptosis of neurons and expressions of β-catenin protein in hippocampusof penicillin-induced epileptic rat models. Methods: Thirty male Sprague-Dawley (SD) rats (weight250±50g) were randomly divided into four groups:blank control (BC) group (n=6), ginsenoside Rb1control (GC) group (n=8),penicillin-induced epileptic (PE) group (n=8) and ginsenoside Rb1treatmentepileptic (GPE) group (n=8). In ginsenoside Rb1control group andginsenoside Rb1treatment epileptic group, the rats were treated with1%ginsenoside Rb13ml/Kg (30mg/Kg) by the way of intraperitoneal injection1hour before the epileptic model preparation. In blank control group andpenicillin-induced epileptic group, the rats were treated with isometric normalsaline (0.9%NaCl solution) by the way of intraperitoneal injection. Bothpenicillin-induced epileptic group and ginsenoside Rb1treatment epilepticgroup were treated with9.5ml/Kg penicillin (800thousands U/ml,7.6millionU/Kg) by the way of intraperitoneal injection. The rats of both blank controlgroup and ginsenoside Rb1control group were treated with isometric normalsaline by the way of intraperitoneal injection. Behavior changes of rats wereobserved for3hour. The seizure intensity of epilepsy in rats was recorded.After that, all rats were anesthetized with3%pentobarbital sodium solution at the dosage of1ml/Kg by the way of intraperitoneal injection. The thoraciccavity was opened to expose the heart. An incision was made in right atrium. Asyringe needle was inserted into ascending aorta through left ventricle, normalsaline was quickly transfused into the aorta, and then500ml4%paraformaldehyde solution was transfused for fixing the organizations of rats.Craniotomy was performed in rats. The brain tissue of rats was removed andsoaked into4%paraformaldehyde solution for8to12hours. The brain wastreated with alcohol solutions for dehydration and with paraffin for embedding.And then4μm thick slices were prepared for further study. The pathologicalchanges of hippocampus were observed through optical microscope stainedwith hematoxylin-eosin staining (HE). The apoptosis of hippocampal neuronswas observed by TdT-mediated dUTP nick-end labeling （TUNEL） method.The expression of β-catenin protein in hippocampus of rats was detected byimmunohistochemical staining method. Results:(1) Behavior changes ofseizure intensity of epilepsy in rats: There were no epileptic seizures and noabnormal performance in both blank control group and ginsenoside Rb1controlgroup rats. In penicillin-induced epileptic group rats, epileptic seizures wereobserved and the intensities of epileptic seizure were up to or above Ⅲ level;among8rats, the seizure intensities of3rats reached Ⅲ level and those of2rats reached Ⅳ level and3rats reached Ⅴ level. In ginsenoside Rb1treatmentepileptic group, epileptic seizures were also observed in rats, but the magnitudeof epileptic seizures was significantly lightened compared with that of penicillin-induced epileptic group. The seizure intensities of epilepsy were lessthan Ⅲ level; among8rats, the seizure intensities of5rats reachedⅡ leveland that of3rats reachedⅠlevel.(2) Histopathologic changes of hippocampalneurons: In blank control group and ginsenoside Rb1control group,morphology and structure of hippocampal neurons were normal. There weredegeneration and necrosis of hippocampal neurons in penicillin-inducedepileptic group and ginsenoside Rb1treatment group rats. However,comparedwith that of penicillin-induced epileptic group the degeneration and necrosis ofhippocampal neurons in ginsenoside Rb1treatment epileptic group rats weresignificantly lightened.(3) The changes of hippocampal neuron apoptosis inrats: Neuron apoptosis was detected in CA1, CA2, CA3and dentate gyrus areaof hippocampus in all groups’ rats. the number of apoptotic hippocampalneurons was counted in blank control group, ginsenoside Rb1control group,penicillin-induced epileptic group and ginsenoside Rb1treatment epilepticgroup (respectively2.5±1.05,1.75±0.71,3.5±0.93and1.63±0.74in CA1area;3.33±1.03,1.50±0.76,6.13±1.23,2.75±0.71in CA2area;3.83±1.17,3.75±0.71,8.38±1.3,5.38±1.19in CA3area;3.5±1.38,3.38±0.92,21.75±3.85,10.88±3.36in dentate gyrus area). Compared with blank control group, the number ofapoptotic hippocampal neurons was obviously increased in penicillin-inducedepileptic group and ginsenoside Rb1treatment epileptic group, and there werestatistically differences (P<0.05). Compared with the penicillin-inducedepileptic group, the number of apoptotic hippocampal neurons was significantly decreased in ginsenoside Rb1treatment epileptic group (P<0.05). The numberof apoptotic hippocampal neurons in ginsenoside Rb1treatment epileptic grouprats was much more than that in ginsenoside Rb1control group(P<0.05).(4)The changes of β-catenin protein expression in hippocampus: The average ODvalues (AO) of β-catenin protein expressions in hippocampus were respectively(16.94±0.17)×10-2,(20.39±2.64)×10-2,(18.79±0.67)×10-2and (17.07±0.5)×10-2in blank control group, ginsenoside Rb1control group, penicillin-inducedepileptic group and ginsenoside Rb1treatment epileptic group. Compared withthe blank group, the β-catenin expression in hippocampus was significantlyincreased in penicillin-induced epileptic group and ginsenoside Rb1treatmentepileptic group (P<0.05). Compared with the penicillin-induced epileptic group,the β-catenin expression in hippocampus was obviously reduced in ginsenosideRb1treatment epileptic group (P<0.05). The β-catenin expression ofhippocampus in ginsenoside Rb1treatment epileptic group rats was lower thanthat in ginsenoside Rb1control group(P<0.05). All these differences werestatistically significant. Conclusions: Neuron apoptosis and β-catenin proteinexpression in hippocampus were increased in penicillin-induced epileptic rats.Ginsenoside Rb1can reduce the intensities of epileptic seizure and decrease theapoptosis of hippocampal neurons and inhibit up-regulations of β-cateninprotein expression in hippocampus of penicillin epileptic rats.