Protocol paper: kainic acid excitotoxicity-induced spinal cord injury paraplegia in Sprague-Dawley rats

BACKGROUND: Excitotoxicity-induced in vivo injury models are vital to reflect the pathophysiological features of acute spinal cord injury (SCI) in humans. The duration and concentration of chemical treatment controls the extent of neuronal cell damage. The extent of injury is explained in relation to locomotor and behavioural activity. Several SCI in vivo methods have been reported and studied extensively, particularly contusion, compression, and transection models. These models depict similar pathophysiology to that in humans but are extremely expensive (contusion) and require expertise (compression). Chemical excitotoxicity-induced SCI models are simple and easy while producing similar clinical manifestations. The kainic acid (KA) excitotoxicity model is a convenient, low-cost, and highly reproducible animal model of SCI in the laboratory. The basic impactor approximately cost between 10,000 and 20,000 USD, while the kainic acid only cost between 300 and 500 USD, which is quite cheap as compared to traditional SCI method. METHODS: In this study, 0.05 mM KA was administered at dose of 10 µL/100 g body weight, at a rate of 10 µL/min, to induce spinal injury by intra-spinal injection between the T12 and T13 thoracic vertebrae. In this protocol, detailed description of a dorsal laminectomy was explained to expose the spinal cord, following intra-spinal kainic acid administration at desired location. The dose, rate and technique to administer kainic acid were explained extensively to reflect a successful paraplegia and spinal cord injury in rats. The postoperative care and complication post injury of paraplegic laboratory animals were also explained, and necessary requirements to overcome these complications were also described to help researcher. RESULTS: This injury model produced impaired hind limb locomotor function with mild seizure. Hence this protocol will help researchers to induce spinal cord injury in laboratories at extremely low cost and also will help to determine the necessary supplies, methods for producing SCI in rats and treatments designed to mitigate post-injury impairment. CONCLUSIONS: Kainic acid intra-spinal injection at the concentration of 0.05 mM, and rate 10 µL/min, is an effective method create spinal injury in rats, however more potent concentrations of kainic acid need to be studied in order to create severe spinal injuries.

Effect of Sirolimus attenuating kainic acid 3 induced epilepsy in mice / 中华实用儿科临床杂志

Objective To explore the therapeutic mechanism of in response to kainic acid－induced epilepsy in mice. Methods Sixty mice Were randomly divided into control group,model group and loW－dose Sirolimus group, medium－dose and high－dose Sirolimus groups. Prevention and therapeutic administration Were used in the Sirolimus loW,medium and high dose groups. One Week before model establishment,intraperitoneal injection of Sirolimus 1 mg／kg,3 mg／kg and 9 mg／kg Were given once a day,but the model group and the control group Were injected intra﹣peritoneally the same dose of 9 g／L saline. One Week after the preventive administration,all mice except the control group,Were intraperitoneally injected 30 mg／kg kainate solution,and the control group Was injected an equal dose of 9 g／L saline. Mice Were treated 1 Week after the establishment of the models. The number of mice With epileptic symp﹣toms and the number of epileptic seizures,the seizure time and the average number of episodes Were recorded,the Mor﹣ris Water maze test Was performed on the mice,and the arrival time,sWimming distance and number of crossing times of the mice Were collected. The expression levels of mTOR pathWay－related protein gene and the number of apoptotic cells in hippocampus Were detected in hippocampus of mice. Results Epilepsy symptoms appeared earlier in the model group after modeling,and the epileptoid－like symptoms Were significantly delayed in each group(P﹦0. 001 9). The epilepsy grading model group Was significantly higher than that of other groups. The mouse seizure time on the 6th day after modeling Was significantly higher than that on the 3rd day after modeling. The time required for the model epileptic mouse to reach the platform and the sWimming length Was significantly more than that of the control group( P ﹦0. 000 1),While the number of the mice traversing the platform Was significantly loWer(P﹦0. 000 2),and the admi﹣nistration group Was significantly relieved. The gene expression levels of mTOR pathWay key proteins mTOR and S6 in the hippocampus of mice in the model group Were significantly up－regulated(P﹦0. 000 1). Simultaneously,different doses of Sirolimus could significantly doWn － regulate PI3K,AKT,mTOR,and S6 gene expression levels( P ﹦0. 000 1). Compared With the control group,the gray ratios of p－PI3K,p－AKT,p－mTOR and p－S6 and normal PI3K,AKT,mTOR and S6 protein in the model group Were significantly higher(P﹦0. 000 1),and Sirolimus Was also observed. It Was significantly doWn－regulated after administration(P﹦0. 000 1). Conclusions Sirolimus can signifi﹣cantly inhibit the over－activation of mTOR signaling pathWay in the hippocampal region of kainic acid－induced epi﹣lepsy mice,thereby alleviating the symptoms of epilepsy in mice and increasing learning and memory.

Akt Inhibitor Perifosine Prevents Epileptogenesis in a Rat Model of Temporal Lobe Epilepsy / 神经科学通报·英文版

Accumulating data have revealed that abnormal activity of the mTOR (mammalian target of rapamycin) pathway plays an important role in epileptogenesis triggered by various factors. We previously reported that pretreatment with perifosine, an inhibitor of Akt (also called protein kinase B), abolishes the rapamycin-induced paradoxical increase of S6 phosphorylation in a rat model induced by kainic acid (KA). Since Akt is an upstream target in the mTOR signaling pathway, we set out to determine whether perifosine has a preventive effect on epileptogenesis. Here, we explored the effect of perifosine on the model of temporal epilepsy induced by KA in rats and found that pretreatment with perifosine had no effect on the severity or duration of the KA-induced status epilepticus. However, perifosine almost completely inhibited the activation of p-Akt and p-S6 both acutely and chronically following the KA-induced status epilepticus. Perifosine pretreatment suppressed the KA-induced neuronal death and mossy fiber sprouting. The frequency of spontaneous seizures was markedly decreased in rats pretreated with perifosine. Accordingly, rats pretreated with perifosine showed mild impairment in cognitive functions. Collectively, this study provides novel evidence in a KA seizure model that perifosine may be a potential drug for use in anti-epileptogenic therapy.

Antiepileptic and anti-neuroinflammatory effects of red ginseng in an intrahippocampal kainic acid model of temporal lobe epilepsy demonstrated by electroencephalography / 영남의대학술지

BACKGROUND: Chronic inflammation can lower the seizure threshold and have influence on epileptogenesis. The components of red ginseng (RG) have anti-inflammatory effects. The abundance of peripherally derived immune cells in resected epileptic tissue suggests that the immune system is a potential target for anti-epileptogenic therapies. The present study used continuous electroencephalography (EEG) to evaluate the therapeutic efficacy of RG in intrahippocampal kainic acid (IHKA) animal model of temporal lobe epilepsy.METHODS: Prolonged status epilepticus (SE) was induced in 7-week-old C57BL/6J mice via stereotaxic injection of kainic acid (KA, 150 nL; 1 mg/mL) into the right CA3/dorsal hippocampus. The animals were implanted electrodes and monitored for spontaneous seizures. Following the IHKA injections, one group received treatments of RG (250 mg/kg/day) for 4 weeks (RG group, n=7) while another group received valproic acid (VPA, 30 mg/kg/day) (VPA group, n=7). Laboratory findings and pathological results were assessed at D29 and continuous (24 h/week) EEG monitoring was used to evaluate high-voltage sharp waves on D7, D14, D21, and D28.RESULTS: At D29, there were no differences between the groups in liver function test but RG group had higher blood urea nitrogen levels. Immunohistochemistry analyses revealed that RG reduced the infiltration of immune cells into the brain and EEG analyses showed that it had anticonvulsant effects.CONCLUSION: Repeated treatments with RG after IHKA-induced SE decreased immune cell infiltration into the brain and resulted in a marked decrease in electrographic seizures. RG had anticonvulsant effects that were similar to those of VPA without serious side effects.

Morin Prevents Granule Cell Dispersion and Neurotoxicity via Suppression of mTORC1 in a Kainic Acid-induced Seizure Model

An abnormal reorganization of the dentate gyrus and neurotoxic events are important phenotypes in the hippocampus of patients with temporal lobe epilepsy (TLE). The effects of morin, a bioflavonoid constituent of many herbs and fruits, on epileptic seizures have not yet been elucidated, though its beneficial effects, such as its anti-inflammatory and neuroprotective properties, are well-described in various neurodegenerative diseases. In the present study, we investigated whether treatment with morin hydrate (MH) can reduce the susceptibility to seizures, granule cell dispersion (GCD), mammalian target of rapamycin complex 1 (mTORC1) activity, and the increases in the levels of apoptotic molecules and inflammatory cytokines in the kainic acid (KA)-induced seizure mouse model. Our results showed that oral administration of MH could reduce susceptibility to seizures and lead to the inhibition of GCD and mTORC1 activity in the KA-treated hippocampus. Moreover, treatment with MH significantly reduced the increased levels of apoptotic signaling molecules and pro-inflammatory mediators in the KA-treated hippocampus compared with control mice, suggesting a neuroprotective role. Therefore, these results suggest that morin has a therapeutic potential against epilepsy through its abilities to inhibit GCD and neurotoxic events in the in vivo hippocampus.

Atorvastatin pretreatment attenuates kainic acid-induced hippocampal neuronal death via regulation of lipocalin-2-associated neuroinflammation

Statins mediate vascular protection and reduce the prevalence of cardiovascular diseases. Recent work indicates that statins have anticonvulsive effects in the brain; however, little is known about the precise mechanism for its protective effect in kainic acid (KA)-induced seizures. Here, we investigated the protective effects of atorvastatin pretreatment on KA-induced neuroinflammation and hippocampal cell death. Mice were treated via intragastric administration of atorvastatin for 7 days, injected with KA, and then sacrificed after 24 h. We observed that atorvastatin pretreatment reduced KA-induced seizure activity, hippocampal cell death, and neuroinflammation. Atorvastatin pretreatment also inhibited KA-induced lipocalin-2 expression in the hippocampus and attenuated KA-induced hippocampal cyclooxygenase-2 expression and glial activation. Moreover, AKT phosphorylation in KA-treated hippocampus was inhibited by atorvastatin pretreatment. These findings suggest that atorvastatin pretreatment may protect hippocampal neurons during seizures by controlling lipocalin-2-associated neuroinflammation.

Cilostazol attenuates kainic acid-induced hippocampal cell death

Cilostazol is a selective inhibitor of type 3 phosphodiesterase (PDE3) and has been widely used as an antiplatelet agent. Cilostazol mediates this activity through effects on the cyclic adenosine monophosphate (cAMP) signaling cascade. Recently, it has attracted attention as a neuroprotective agent. However, little is known about cilostazol's effect on excitotoxicity induced neuronal cell death. Therefore, this study evaluated the neuroprotective effect of cilostazol treatment against hippocampal neuronal damage in a mouse model of kainic acid (KA)-induced neuronal loss. Cilostazol pretreatment reduced KA-induced seizure scores and hippocampal neuron death. In addition, cilostazol pretreatment increased cAMP response element-binding protein (CREB) phosphorylation and decreased neuroinflammation. These observations suggest that cilostazol may have beneficial therapeutic effects on seizure activity and other neurological diseases associated with excitotoxicity.

Correlation between uric acid level in the hippocampus and epilepsy in a mouse model with acute limbic seizures / 实用医学杂志

Objective To investigate correlation between seizures and uric acid level in the hippocampus in a mouse model with acute limbic seizures by pharmacological and genetic method. Methods Normal male C57BL/6 and mutant mice were used in this study,including urate oxidase overexpression (UOx-OE) and urate oxidase knock-out (UOx-KO) ;These mice were divided into the following groups,including the control,KA, All ,OE ,KO group respectively;during the experiment ,behaviors ,latency and duration time were recorded;dialysates were collected by microdialysis technique and uric acid level was detected by FPLC;Uric acid in the hippocampus,seizures status,latency and duration were compared. Results Twenty-four mice in total were enrolled and only 1 death occurred until the end of the study. Seizures state appeared after KA treatment. Compared to the KA group,uric acid and generalized seizures declined by the treatment of KA and All (P 0.05). Conclusions Uric acid level in the hippocampus of mice may have effects on seizures ,in which it suggests that uric acid and its relevant signal pathway could be a potential therapy target in seizures clinically.

Study on glycyrrhizin in reducing neuronal damage by inhibiting high mobility group protein 1 in immature rats with epilepsy / 中华实用儿科临床杂志

Objective To study the effect of glycyrrhizin(GL) on the gene expression of high mobility group protein 1 (HMGB1) in hippocampus and serum.To evaluate the effect on the expression of neuron-specific nuclear-binding protein (Neu-N) in the hippocampus CA1,CA3 regions in the chronic stage of an immature rat epilepsy model.Methods Fifty-two 21 day-old SD rats were randomly divided into control group,model group Ⅰ and model group Ⅱ according to the random table method.Model group Ⅰ was induced epilepsy by kainic acid (KA),and the model group Ⅱ was pretreated with GL by intraperitoneal injection at 30 min before KA injection.According to the different observation time points,each group was divided into 4 subgroups:3 h,12 h,24 h and 7 d.Model group Ⅱ was divided into 3 subgroups:10 mg/kg,50 mg/kg,100 mg/kg,according to the different doses of GL.There were 3 animals in each subgroup.Score was performed according to the Racine score,and quantitative real-time polymerase chain reaction and Western blot were applied to detect the mRNA and protein expression of HMGB1 in the acute phase.Enzyme-linked immunosorbent assay(ELISA) was applied to measure the expression of HMGB1 in blood;immunohistochemical was applied to measure the expression of Neu-N in hippocampus in the chronic phase(7 d).Results Compared with model group Ⅰ,seizure onset time was obviously prolonged in model group Ⅱ [(24.08 ± 1.98) min vs.(33.39 ± 2.66) min],and the difference was statistically significant (t =9.231,P ＜0.05);Comparing KA model group Ⅰ with control group,the gene expression of HMGB1 significantly increased,and reached a peak at the time of 12 h (H =10.532,P ＜ 0.05),but the protein expression of HMGB1 was changed obviously and there was no significant difference (H =5.227,P ＞0.05).The expression of HMGB1 in the serum also significantly increased,especially at 12 h (H =6.897,P ＜0.05).At the time of 12 h after KA injection,the gene expression of HMGB1 in the hippocampus was significantly decreased in model group Ⅱ compared with model group Ⅰ (H =10.721,P ＜0.05) (especially in the 100 mg/kg model group).Also,the expression of HMGB1 in the scrum was obviously decreased (H =6.967,P ＜ 0.05) (especially in the 100 mg/kg model group).At the time of 7 d after KA injection,hippocampal neuron loss in model group.Ⅰ was significantly reduced compared with control group (P ＜ 0.05),and hippocampal neuron loss in model group Ⅱ was evidently decreased compared with model group Ⅰ (P ＜ 0.05),(especially in the 100 mg/kg model group in CA1,50 mg/kg model group in CA3).Conclusions In the immature rat temporal lobe epilepsy model,GL may have neuroprotective by inhibiting the synthesis and release of HMGB1,inhibiting inflammation further to restrain the loss of neurons in the chronic phase.

Anticonvulsant effect of ceftriaxone sodium in temporal lobe epilepsy / 基础医学与临床

Objective To study the effects of ceftriaxone sodium(Cef) on the seizures and the expression of glutamate transporter (GLT-1) in kainic acid (KA) epilepsy model.Methods Firstly, a chronic spontaneous seizure mouse model was established by unilateral hippocampal injection of KA and monitored by vEEG technique to record seizures.The experimental group received intraperitoneal injection of Cef 200 mg/(kg·d) and the control group received normal saline.Seizure frequency, interictal spike waves and histological phenotypes were recorded to evaluate the function of Cef.Then we use the Western blot to detect the effect of expression for GLT-1.Results Unilateral hippocampal injection of KA 200 ng successfully established the mesial temporal lobe epilepsy model.Cef can reduce the seizures from 2.145 times/day to 1.597 times/day, decreased by 31.2% with a statistical significance(P<0.05).Cef treatment did not significantly enhance the expression of GLT-1.Conclusions Intraperitoneal injection of Cef partially inhibites the seizures of KA model, but the expression of GLT-1 in hippocampus is not enhanced.It is suggested that ceftriaxone may inhibit seizures through other mechanisms.

Up-regulation of TRPC3 in the Cortex of Rats with Kainic Acid-induced Seizures / 华中科技大学学报(医学版)

Objective To observe the expression change of TRPC3 in cortex of rats with Kainic acid(KA)-induced sei-zures,and to explore the role of TRPC3 in epileptogenesis.Methods Fifty-four adult Sprague Dawley(SD)rats were randomly divided into two groups(18 for control group,36 for epilepsy group).The behavior of rats was observed and recorded.The epi-lepsy group was treated with KA(2 μg/kg,about 7 μL,lateral intracerebroventricular injection),and control group was treated with isotonic Nachloride(equivalent volume with KA,lateral intracerebroventricular injection).For epilepsy group,samples were taken 48 and 72 h after seizure burst.For control group,samples were taken 48 h after isotonic Nachloride injection.The mRNA level of TRPC3 in cortex was detected and recorded by RT-PCR,and the protein level of TRPC3 in cortex was measured by Western blotting,and immunohistochemistry was also used to display the TRPC3 expression in cortex.Results The control group showed no seizure activity,and the epilepsy group showed classical seizure activity(Ⅳ-Ⅴ level)about 5 min after injection and last for several hours.The mRNA and protein levels of TRPC3 in epilepsy group were both higher than those in control group with obvious distinction(P< 0.05).Conclusion The TRPC3 level increases in cortex of rats with KA-induced sei-zures.These results point out that TRPC3 is possibly involved in epilepsy etiopathogenesis and development.

Beneficial Effects of Silibinin Against Kainic Acid-induced Neurotoxicity in the Hippocampus in vivo

Silibinin, an active constituent of silymarin extracted from milk thistle, has been previously reported to confer protection to the adult brain against neurodegeneration. However, its effects against epileptic seizures have not been examined yet. In order to investigate the effects of silibinin against epileptic seizures, we used a relevant mouse model in which seizures are manifested as status epilepticus, induced by kainic acid (KA) treatment. Silibinin was injected intraperitoneally, starting 1 day before an intrahippocampal KA injection and continued daily until analysis of each experiment. Our results indicated that silibinin-treatment could reduce seizure susceptibility and frequency of spontaneous recurrent seizures (SRS) induced by KA administration, and attenuate granule cell dispersion (GCD), a morphological alteration characteristic of the dentate gyrus (DG) in temporal lobe epilepsy (TLE). Moreover, its treatment significantly reduced the aberrant levels of apoptotic, autophagic and pro-inflammatory molecules induced by KA administration, resulting in neuroprotection in the hippocampus. Thus, these results suggest that silibinin may be a beneficial natural compound for preventing epileptic events.

A Model of Glial Scarring Analogous to the Environment of a Traumatically Injured Spinal Cord Using Kainate

OBJECTIVE: To develop an in vitro model analogous to the environment of traumatic spinal cord injury (SCI), the authors evaluated change of astrogliosis following treatments with kainate and/or scratch, and degree of neurite outgrowth after treatment with a kainate inhibitor. METHODS: Astrocytes were obtained from the rat spinal cord. Then, 99% of the cells were confirmed to be GFAP-positive astrocytes. For chemical injury, the cells were treated with kainate at different concentrations (10, 50 or 100 µM). For mechanical injury, two kinds of uniform scratches were made using a plastic pipette tip by removing strips of cells. For combined injury (S/K), scratch and kainate were provided. Cord neurons from rat embryos were plated onto culture plates immediately after the three kinds of injuries and some cultures were treated with a kainate inhibitor. RESULTS: Astro-gliosis (glial fibrillary acidic protein [GFAP], vimentin, chondroitin sulfate proteoglycan [CSPG], rho-associated protein kinase [ROCK], and ephrin type-A receptor 4 [EphA4]) was most prominent after treatment with 50 µM kainate and extensive scratch injury in terms of single arm (p<0.001) and in the S/K-induced injury model in view of single or combination (p<0.001). Neurite outgrowth in the seeded spinal cord (β-III tubulin) was the least in the S/K-induced injury model (p<0.001) and this inhibition was reversed by the kainate inhibitor (p<0.001). CONCLUSION: The current in vitro model combining scratch and kainate induced glial scarring and inhibitory molecules and restricted neurite outgrowth very strongly than either the mechanically or chemically-induced injury model; hence, it may be a useful tool for research on SCI.

Kainic Acid Treatment Increases Ca²⁺-mediated Neurotoxicity in the Mouse Hippocampus / 체질인류학회지

Kainic acid (KA)-induced neuronal cell death is associated with intracellular Ca²⁺ influx. However, it is unknown whether Lyn/Btk pathway is involved in the Ca²⁺-mediated neurotoxicity and neuronal death induced by KA. In the present study, we investigated the altered expression of Ca²⁺-controlled proteins in KA-treated hippocampus. Mice were sacrificed at 24 h after KA (20 mg/kg) systemic injection. We conducted Electroencephalographic (EEG) recording and examined hippocampal alterations by Western blotting and immunostaining in control mice or KA-treated mice. EEG tests showed that KA-treated mice increased seizure frequency and severity compared with control mice during KA-induced seizures. We found that KA decreases hippocalcin and calpain-mediated proteolysis in the hippocampus. In particular, the phosphorylation of Lyn and Btk was increased in KA-treated hippocampus compared to those of control mice. Our findings identify tyrosine kinases such as Lyn/Btk as a critical regulator of Ca²⁺-mediated neurotoxicity in KA-induced seizures.

Effect of Pioglitazone on Excitotoxic Neuronal Damage in the Mouse Hippocampus

Pioglitazone (PGZ), a synthetic peroxisome proliferator-activated receptor gamma agonist, is known to regulate inflammatory process and to have neuroprotective effects against neurological disorders. In the present study, we examined the effects of 30 mg/kg PGZ on excitotoxic neuronal damage and glial activation in the mouse hippocampus following intracerebroventricular injection of kainic acid (KA). PGZ treatment significantly reduced seizure-like behavior. PGZ had the neuroprotective effect against KA-induced neuronal damage and attenuated the activations of astrocytes and microglia in the hippocampal CA3 region. In addition, MPO and NFkappaB immunoreactivities in the glial cells were also decreased in the PGZ-treated group. These results indicate that PGZ had anticonvulsant and neuroprotective effects against KA-induced excitotocix injury, and that neuroprotective effect of PGZ might be due to the attenuation of KA-induced activation in astrocytes and microglia as well as KA-induced increases in MPO and NFkappaB.

Intracerebroventricular Kainic Acid-Induced Damage Affects Blood Glucose Level in d-glucose-fed Mouse Model

We have previously reported that the intracerebroventricular (i.c.v.) administration of kainic acid (KA) results in significant neuronal damage on the hippocampal CA3 region. In this study, we examined possible changes in the blood glucose level after i.c.v. pretreatment with KA. The blood glucose level was elevated at 30 min, began to decrease at 60 min and returned to normal at 120 min after D-glucose-feeding. We found that the blood glucose level in the KA-pretreated group was higher than in the saline-pretreated group. The up-regulation of the blood glucose level in the KA-pretreated group was still present even after 1~4 weeks. The plasma corticosterone and insulin levels were slightly higher in the KA-treated group. Corticosterone levels decreased whereas insulin levels were elevated when mice were fed with D-glucose. The i.c.v. pretreatment with KA for 24 hr caused a significant reversal of D-glucose-induced down-regulation of corticosterone level. However, the insulin level was enhanced in the KA-pretreated group compared to the vehicle-treated group when mice were fed with D-glucose. These results suggest that KA-induced alterations of the blood glucose level are related to cell death in the CA3 region whereas the up-regulation of blood glucose level in the KA-pretreated group appears to be due to a reversal of D-glucose feeding-induced down-regulation of corticosterone level.

Kainic acid-induced endoplasmic reticulum stress model / 中国组织工程研究

BACKGROUND:Previous studies have shown that kainic acid injected into hippocampus can significantly upregulate the expression of excitatory KA1 subunit of the kainate receptor in the hippocampus, and endoplasmic reticulum stress markers, phosphorylation of the alpha subunit of eukaryotic initiation factor 2, accompanied by celldeath. OBJECTIVE:To explore the mechanism of endoplasmic reticulum stress after kainic acid is injected into the hippocampus.METHODS:0.15 nmol kainic acid was injected into the hippocampal CA1 region of 32 adult male Kunming mice, the injection time was 60 seconds. At different time points (1, 2, 3, 4, 5, 6, 8 and 12 hours) after kainic acid was injected, the Bederson score analysis was performed, and then the brain was harvested after cerebral perfusion. FJB staining of brain sections and immunofluorescence double labeled observation were also performed. RESULTS AND CONCLUSION:(1) At 3, 4, 5, 6, 8 hours after kainic acid injection, Bederson score showed severe injury of central nervous system function, and FJB staining showed the increased of celldeath in the hippocampus (P0.05). (2) According to the results of FJB staining, the brain sections were selected at 3, 8 hours for immunohistochemistry. The expressionlevels of KA1 receptors and endoplasmic reticulum stress marker P-eIF2αwere up-regulated at the same time after kainic acid was injected into hippocampus. Two single-staining KA1 and P-eIF2αimmunofluorescence images were synthesized into one over-lapped double-stained image, and two images overlapped, indicating that the up-regulated expression of KA1 and endoplasmic reticulum stress occurred in the same nerve cells. Kainic acid first up-regulated the excitatory receptor KA1 expression, which may cause cellendoplasmic reticulum dysfunction and result in the endoplasmic reticulum stress response, further promoting neuronal celldeath.

Protective effect of allopurinol in kainic acid-induced epileptic rats / 实用医学杂志

Objective To investigate the protective effect of allopurinol in kainic acid-induced epileptic rats and to explore new ideas and methods for the clinical treatment of epilepsy. Methods 120 Wistar rats were randomly divided into sham group, KA epilepsy group and allopurinol groups. Six rats of each group were randomly selected and were given electrodes into their left frontal and hippocampal regions. After injection, behavior changes were observed in all rates without electrodes. 24 h later, MDA level and SOD enzymatic activity of the left hippocampi were measured. One week later, the EEGs were recorded in rates with electrode, as well as total time of seizures /30 min and numbers of seizures / 30 min. Results Compared with the KA model group, latency period of the epilepsy in the allopurinol group was longer (P < 0.05) and the extent was lighter (P < 0.05); the MDA level was significantly lower (P < 0.01), the SOD enzymatic activity was significantly higher (P < 0.01). The total time of seizures / 30min and numbers of seizures / 30 min in allopurinol group reduced significantly (P < 0.01). Conclusion Allopurinol has potential antiepileptic and antioxidative activities in kainic acid-induced epileptic rats.

Correlation between peripheral blood inflammatory cytokines and kainic acid-induced seizure severity in rats / 中华行为医学与脑科学杂志

Objectives To investigate the correlation between the level of peripheral blood inflammatory cytokines and kainic acid-induced seizure severity in rats.Methods 140 rats were divided into control and model group randomly,70 rats in each group.Model group rats were injected with kainic acid (10 mg/kg) by intraperitoneal,and the control rats were injected with sodium chloride.The change of their behaviors was observed and the concentrations of TNF-α,IL-1β,IL-4 and IL-10 were determined by ELISA in each group at different times.Results The rats showed epilepsy grand mal in 3 h-9 h after KA injection.The concentrations of TNF-α and IL-1β in model groups were significantly higher than those in control group in 6 h-12 h (6 h:(21.5±3.2) pg/ml vs (12.3±3.1)pg/ml;12 h:(20.6±4.2)pg/ml vs (11.5±3.8)pg/ml)(P＜0.05) and IL-4 in model group was higher at only 12 h ((53.55±3.08) pg/ml vs (33.26±4.16)pg/ml) (P＜0.05).The level of IL-10 in model groups was not statistically significant compared with control group (P＞0.05).Conclusion The proinflammatory cytokines (TNF-α and IL-l β) participate in the seizure procedure,meanwhile their levels and seizure severity have eminent correlations,but antiinflammatory cytokines (IL-4 and IL-10) had not.

ID4 mediates proliferation of astrocytes after excitotoxic damage in the mouse hippocampus / 대한해부학회지

Inhibitor of DNA binding (ID) proteins bind to and inhibit the function of basic helix-loop-helix transcription factors, including those that regulate proliferation and differentiation during development. However, little is known about the role of ID proteins in glial activation under neuropathological conditions. In this study, we evaluated the expression of ID4 following induction of excitotoxic lesions in mouse brain by kainic acid injection. The number of ID4-expressing astrocytes increased in the CA1 layer of the injured hippocampus until 3 days post-lesion. To analyze the effects of ID4 on cell proliferation, primary astrocytes were transduced with recombinant adenovirus expressing GFP-ID4. Overexpression of ID4 led to increased proliferation of astrocytes. These results suggest that ID4 plays a proliferative role in astrocyte activation after excitotoxin-induced hippocampal neuronal death.