5-羟色胺1A受体激动剂8-OH-DPAT对癫痫合并抑郁大鼠的干预作用及其机制研究

目的 探讨5-羟色胺1A(5-HT1A)受体激动剂8-OH-DPAT对癫痫合并抑郁大鼠的干预作用及其机制.方法 成年级SD大鼠160只,随机选取8只为正常对照组,其余大鼠采用匹罗卡品诱导慢性癫痫大鼠模型.25 d后通过体质量与摄食量测量及旷场试验筛选出癫痫合并抑郁模型大鼠32只,随机分为模型组、卡马西平(CBZ)组、CBZ+ 8-OH-DPAT低剂量组(8-OH-DPAT低剂量组)及CBZ+ 8-OH-DPAT高剂量组(8-OH-DPAT高剂量组);分别给予CBZ 100 mg/kg、CBZ +8-OH-DPAT 0.1mg/(kg·d)、CBZ+ 8-OH-DPAT 1 mg/(kg·d).连续治疗7d后,进行癫痫发作的Racine分级、体质量、摄食量测量及旷场试验;采用荧光实时定量聚合酶链反应测定大鼠海马齿状回神经生长因子(NGF) mRNA表达,免疫组化染色观察苔藓纤维出芽(M FS).结果 治疗后,与正常对照组比较,模型组、CBZ组、8-OH-DPAT低、高剂量组的体质量与摄食量明显下降,海马NGF mRNA表达与Timm评分明显增高(均P＜0.05).与模型组比较,CBZ组、8-OH-DPAT低、高剂量组的体质量、摄食量及旷场试验评分明显提高,Racine分级、海马NGF mRNA表达与Timm评分明显下降(均P＜0.05);其中8-OH-DPAT高剂量组上述改变更明显(均P＜0.05).结论 高剂量的5-HT1A受体激动剂8-OH-DPAT能抑制癫痫合并抑郁大鼠海马齿状回的MFS和神经生长因子的表达,促进海马神经重塑.这可能是5-HT1A受体激动剂抗癫痫、抗抑郁的分子机制之一.     

匹罗卡品诱发成年大鼠普遍癫痫与难治性癫痫海马神经发生的变化

背景：神经发生包括细胞增殖、迁移、分化和存活等,是人和多数哺乳动物部分脑区产生新生神经元的过程,主要分布在侧脑室下区和海马齿状回。癫痫可导致海马齿状回的神经发生改变,BrdU是目前公认最理想检测未成熟细胞增殖的标记物之一。 目的：观察匹罗卡品诱发成年大鼠癫痫后神经发生的特点,以及普通癫痫与难治性癫痫神经发生的差异。 设计、时间及地点：随机分组,细胞分子生物学实验,于2006-08/2007-06在华中科技大学同济医学院中心实验室及附属协和医院中心实验室完成。 材料：选用健康Sprague-Dawley雄性大鼠100只,随机分为2组,对照组8只,实验组92只,分为普通癫痫组,自发发作组,难治性癫痫组和非耐药组。匹罗卡品为武汉晶美公司产品,兔抗鼠BrdU抗体为美国sigma公司产品,辣根过氧化物酶标记的羊抗兔IgG为武汉博士德公司产品。 方法：对照组大鼠腹腔注射生理盐水;实验组腹腔注射匹罗卡品15mg/kg,最多注射4次,出现癫痫持续状态的大鼠注射水合氯醛终止发作。致癫大鼠癫痫发作终止后6h腹腔注射BrdU,观察自发发作情况。以脑电图、自发发作频率持续时间,无自发发作为普通癫痫组,有自发发作为自发发作组。行卡马西平灌胃2周并记录发作频率,对卡马西平治疗无效,发作频率减少<50%的为难治性癫痫组,治疗有效即发作频率减少>50%为非耐药组。普通癫痫组分别于注射后第1,2,3,7,14,21和28d取鼠脑海马部做冠状连续切片。非耐药组和难治性癫痫组的大鼠,再次行腹腔注射BrdU,每次为50mg/kg,连续注射4次,每次间隔2h,48h后取脑海马部制作石蜡切片。 主要观察指标：脑海马部切片行免疫组化染色,镜下观察不同时间点BrdU阳性细胞的分布、形态和数量及注射匹罗卡品后大鼠癫痫发作状况。 结果：匹罗卡品第1次注射后所有大鼠无癫痫发作,第2次注射发作16只,第3次注射发作42只,第4次注射后发作11只,14只大鼠4次注射仍无癫痫发作,9只大鼠癫痫持续状态后死亡,77只进入结果分析。神经发生主要位于海马颗粒细胞层和齿状回。与对照组比较,普通癫痫组BrdU阳性细胞明显增多（P<0.01）,难治性癫痫组新生细胞较普通癫痫组明显减少（P<0.01）,神经发生减少。癫痫后第2天BrdU 阳性细胞数目开始增加,14-15d达到高峰,1个月后回到初始水平。 结论：与普通癫痫相比,难治性癫痫可导致神经发生减少。     

匹罗卡品诱导癫痫大鼠内源性神经干细胞的可塑性改变

目的探讨匹罗卡品诱导癫痫模型的内源性神经干细胞的增殖、迁移,从而研究癫痫发生后的神经发生及可塑性改变.方法氯化锂和匹罗卡品联合诱导大鼠癫痫模型,分为对照组、癫痫发作后3、7、14、28 d组,用免疫组织化学方法动态检测大鼠海马多唾液酸神经细胞粘附分子(polysiolylated neural cell adhesion molecule,PSA-NCAM)及PSA-NCAM/5-溴脱氧尿苷嘧啶(bromodeoxyuridine,BrdU)的表达.结果与对照组比较,海马齿状回(dentate gyrus,DG)PSA-NCAM及PSA-NCAM/BrdU的阳性细胞在癫痫后3 d开始增加(P＜0.05),14 d达到高峰(P＜0.05),28 d后开始下降,但仍高于对照组(P＜0.05).结论癫痫发生后出现神经干细胞的增殖、迁移,也即出现了神经发生和可塑性改变.     

5-羟色胺1A受体激动剂8-OH-DPAT改善帕金森病运动并发症的实验研究

目的 探讨5-羟色胺1A(5-HT1A)受体激动剂8-OH-DPAT对左旋多巴诱发的运动并发症的细胞学与行为学效应.方法 通过6-羟基多巴胺立体定向注射至大鼠前脑内侧前脑束建立帕金森病(Parkinson disease,PD)动物模型.对模型成功的PD大鼠进行两套实验:第1套实验中3组PD大鼠接受每日2次左旋多巴甲酯(50 mg/kg加12.5 mg/kg苄丝肼)腹腔注射,持续22 d.在第23天左旋多巴注射前,3组PD大鼠先分别接受8-OH-DPAT、8-OH-DPAT+5-羟色胺1A(5-HT1A)受体阻断剂WAY-100635(0.1 mg/kg)及溶剂对照注射;第2套实验中2组PD大鼠每日2次分别接受左旋多巴/苄丝肼+8-OH-DPAT与左旋多巴/苄丝肼+溶剂,持续22 d.评估旋转时间、关期发生频率情况;采用蛋白印迹法检测纹状体区谷氨酸受体1(GluR1)亚细胞分布及GluR1的845位丝氨酸(GluR1Ser845)磷酸化的表达情况.结果 8-OH-DPAT逆转了左旋多巴所诱导的PD大鼠旋转时间的缩短,延长约27.8%±6.1%;并使关期发生频率减少约7.2%±1.7%.5-HT1A受体阻断剂WAY-100635与8-OH-DPAT联合应用则消除了8-OH-DPAT的效应,提示所观察到的8-OH-DPAT的效应是通过5-HT1A受体起作用的.此外,8-OH-DPAT能调节与运动并发症密切相关的GluR1的亚细胞分布,且使GluR1Ser845的磷酸化水平降低约22.1%±3.5%.结论 激动5-HT1A受体的药物可能是治疗及预防PD运动并发症有益的疗法.     

匹罗卡品癫痫大鼠海马TrkB受体表达与苔藓纤维突触重建的关系

目的 探讨匹罗卡品诱导慢性癫痫大鼠海马齿状颗粒细胞苔藓纤维突触重建与神经营养素受体TrkB表达的关系。方法 取匹罗卡品诱导大鼠急性癫痫持续状态及慢性自发性颞叶癫痫发作期大鼠脑片，用免疫组织化学方法检测TrkB及突触体素(P38，一种突触形成标志物)在大鼠海马的表达。结果 急性癫痫持续状态诱导颗粒细胞表达TrkB一过性增高，第2次表达高峰呈现在7～30d；P38免疫反应性在齿状回内分子层则呈进行性增加，与neo-Timm显示的异常苔藓纤维出芽相一致。结论 TrkB受体激活有助于海马齿状回苔藓纤维轴突生长及突触形成从而有利于颞叶癫痫的发生。     

不同程度的性发作对成年大鼠空间学习记忆影响的研究

目的研究不同程度的性发作对成年大鼠空间学习记忆的影响。方法采用氯化锂和匹罗卡品联合诱导大鼠不同程度的癫模型(轻型和重型)。于造模后第6d给所有大鼠腹腔注射5-溴脱氧尿苷嘧啶(BrdU+)标记海马齿状回增殖的内源性神经前体细胞;用免疫组化方法观察各组大鼠注射BrdU+后第1d和第28d齿状回BrdU+阳性细胞数以及第28d的BrdU+/神经元核性蛋白(NeuN+)阳性细胞数及分布情况;利用Morris水迷宫评价大鼠的学习记忆功能。结果与正常组及轻型组比较,在各个时间点重型组海马齿状回BrdU+细胞数均增加(P<0.05),28d时BrdU+/NeuN+细胞数相应增多,但其占BrdU+细胞数的比例明显下降(P<0.05)。28d时重型组大鼠的学习记忆功能较正常组及轻型组明显下降(P<0.05)。结论严重的癫发作造成大鼠对空间学习记忆功能的损害,可能与其刺激大鼠海马齿状回内源性神经前体细胞增殖水平,抑制其分化为新生的成熟神经元有关。     

甘草甜素对癫痫持续状态大鼠神经保护作用及机制研究

目的研究甘草甜素(glycyrrhizin,GL)对癫痫持续状态大鼠(status epilepticus,SE)神经损伤保护作用及相关分子机制。方法取清洁健康成年雄性SD大鼠60只,采用腹腔注射氯化锂-匹罗卡品的方法建立大鼠癫痫持续状态(SE)模型,随机分为甘草甜素组(SE+GL)和生理盐水组(SE+S),分别经尾静脉给予甘草甜素及生理盐水进行干预,取正常大鼠作为对照组(control group,C);根据给予GL剂量不同将其分为高剂量组(HGL,20 mg/kg)、中剂量组(MGL,10 mg/kg)及低剂量组(LGL,5 mg/kg);通过尼氏染色(NS)观察各组大鼠SE后24 h时大脑皮质神经元损伤情况,分别采用酶联免疫吸附法(ELISA)和蛋白印迹实验(Western blot)检测各组大鼠SE后24 h时血清及大脑皮质中高迁移率族蛋白(HMGB1)的表达水平。结果 SE+S组大鼠大脑皮质神经元在癫痫持续状态后24 h明显受损,SE+GL各组皮质受损神经元数量较SE+S组减少,且在不同给药剂量组间存在显著差异(P0.05);SE+GL各组在SE后24 h时大脑皮质及血清中HMGB1的表达水平较SE+S组显著降低,差异具有统计学意义(P0.05)。结论经尾静脉给予GL能有效地减少SE后大鼠大脑皮质神经元损伤,且其神经保护作用呈剂量依赖性,其机制可能与其抑制血清及大脑皮质炎性因子HMGB1的表达有关。     

人参皂甙Rd对颞叶癫大鼠学习记忆能力及海马5-HT表达的影响

目的研究人参皂甙Rd对氯化锂-匹罗卡品点燃颞叶癫(temporal lobe epilepsy,TLE)大鼠学习记忆能力及海马5-HT表达的干预作用。方法建立氯化锂-匹罗卡品点燃颞叶癫大鼠模型,将30只造模成功的颞叶癫大鼠随机分为TLE组(生理盐水10ml/kg腹腔注射,15只)及GSRd干预组(人参皂甙Rd2mg/kg腹腔注射,15只),另选15只大鼠作为正常对照组;采用Morris水迷宫及免疫组化染色分别检测各组大鼠学习记忆能力及海马5-HT表达水平。结果与正常对照组比较,TLE组大鼠学习记忆能力下降,海马5-HT表达明显减少(P0.05);与TLE组比较,GSRd干预组可显著提高大鼠学习记忆能力及海马5-HT的表达水平(P0.05)。结论人参皂甙Rd可能通过增加海马5-HT的表达来提高颞叶癫大鼠学习记忆能力。     

丁苯酞预处理对缺血再灌注损伤后大鼠海马神经元的保护作用

目的探讨丁苯酞(NBP)预处理对脑缺血再灌注损伤后大鼠海马神经元的保护作用。方法将120只SD大鼠随机分为假手术组、缺血再灌注组、NBP低剂量预处理组(低剂量组)、NBP中剂量预处理组(中剂量组)和NBP高剂量预处理组(高剂量组),每组24只大鼠。低、中、高剂量组大鼠分别给予20 mg/kg、40 mg/kg、80 mg/kg NBP预处理。采用改良Zea Longa线栓法制备脑缺血再灌注模型。2%氯化三苯基四氮唑(TTC)染色测量梗死体积,免疫组织化学法观察5-羟色胺(5-HT)阳性细胞数,免疫印迹法检测5-HT蛋白水平。结果 NBP低剂量组、中剂量组、高剂量组脑梗死体积显著小于缺血再灌注组(均P0.05)。中剂量组与高剂量组脑梗死体积显著小于低剂量组(均P0.05)。与假手术组比较,缺血再灌注组大鼠海马中5-HT阳性细胞数及蛋白表达明显降低(均P0.01)。与缺血再灌注组比较,NBP低、中、高剂量组的5-HT阳性细胞数及蛋白表达显著增加(均P0.05)。中剂量组与高剂量组5-HT阳性细胞数及蛋白表达显著高于低剂量组(均P0.05),高剂量组与中剂量组差异无统计学意义。结论丁苯酞预处理具有脑保护作用,其机制可能为上调缺血海马半暗带区5-HT表达。     

卡马西平对匹罗卡品诱导成年癫间疒大鼠海马齿状回神经前体细胞增殖的影响

目的研究卡马西平对成年癫大鼠海马齿状回内源性神经前体细胞增殖的影响。方法采用氯化锂和匹罗卡品联合诱导大鼠癫模型,将癫大鼠随机分为癫对照组和癫卡马西平组,正常大鼠随机分为正常对照组和正常卡马西平组。癫对照组和正常对照组给以蒸馏水灌胃,同时癫卡马西平组和正常卡马西平组给予卡马西平灌胃。于灌胃后第6d腹腔注射5-溴脱氧尿苷嘧啶(BrdU)标记海马齿状回的内源性神经前体细胞的增殖情况;用免疫组化方法观察各组大鼠在注射BrdU后第1d、第7d齿状回BrdU阳性细胞数量的表达。结果①注射BrdU后第1d,癫对照组大鼠海马齿状回BrdU阳性细胞数较正常对照组明显增加(P<0.01),癫卡马西平组大鼠海马齿状回BrdU阳性细胞数较癫对照组减少(P<0.05);②注射BrdU后第7d,癫对照组大鼠海马齿状回BrdU阳性细胞数较正常对照组明显增加(P<0.01),癫卡马西平组大鼠海马齿状回BrdU阳性细胞数较癫对照组明显减少(P<0.05)。结论卡马西平抑制癫大鼠海马齿状回内源性神经前体细胞增殖。     

8-hydroxy-dipropylaminotetralin promotes neural plasticity in epileptic rats with depression

Rats with chronic pilocarpine-induced temporal lobe epilepsy complicated with depression were studied. Anti-5-bromodeoxyuridine immunofluorescence staining and Timms staining showed that neurogenesis within the hippocampal dentate gyrus and mossy fiber sprouting were increased in model rats. Neurogenesis within the hippocampal dentate gyrus was further enhanced, while mossy fiber sprouting was decreased in model rats administered carbamazepine alone or in combination with the 5-hydroxytryptamine 1A receptor agonist, 8-hydroxy-dipropylaminotetralin (0.1 and 1 mg/kg). Among the groups, the effect was the most significant in rats receiving carbamazepine in conjunction with 1 mg/kg 8-hydroxy-dipropylaminotetralin. Thus, high dose 8-hydroxy-dipropylaminotetralin can improve neural plasticity in epileptic rats with depression.     

NDRG2通过Hes1参与癫痫发作后海马齿状回的神经发生

目的 探讨N-Myc下游调节基因2(N-Myc downstream regulated gene 2,NDRG2)与癫痫发作后海马齿状回神经发生的关系。方法 C57BL/6小鼠20只,随机分为癫痫组和对照组,每组又分为癫痫造模后1和7 d两个时间点,每个时间点5只,通过蛋白免疫印迹检测癫痫后海马齿状回NDRG2蛋白相对表达水平和mRNA相对表达水平变化; 使用双皮质素(DCX)染色标记未成熟神经元,神经巢蛋白(Nestin)标记神经干细胞,神经核蛋白(NeuN)标记成熟神经元,观察NDRG2对海马齿状回神经干细胞增殖影响; 采用RT-PCR检测发状分裂相关增强子1(hairy and enhancer of split 1,Hes 1)、NDRG2 mRNA相对表达表达水平,并分析两者之间的相关性; 观察NDRG2参与癫痫发作后神经发生的可能机制。结果 癫痫组与对照组比较,DCX、Nestin、NeuN、Hes1、NDRG2蛋白相对表达水平在1和7 d这2个时间点有显著性增高,并随时间逐渐递增。结论 癫痫发作后海马NDRG2蛋白相对表达水平增高,与癫痫发作后海马齿状回的神经细胞增值时间具有一致性和相关性,NDRG2可能参与癫痫发作后海马齿状回的神经发生过程; 同时发现海马NDRG2表达增加和Hes1分子表达增加具有相关性,故推测NDRG2可能通过Hes1参与癫痫发作后海马齿状回的神经发生。     

新生期大鼠反复痫性发作的形态学及行为学结果与糖皮质激素水平升高有关

目的探讨新生期大鼠反复痫性发作后的形态学,行为学以及糖皮质激素水平的变化。方法64只出生后一天的Wistar大鼠随机分为惊厥组40只和对照组24只。惊厥组的新生鼠在出生后1天（P1）、4天（P4）、7天（P7）给予腹腔注射匹罗卡品,制备新生鼠癫痫模型;对照组的新生鼠腹腔注射生理盐水。惊厥组分别在第3次致痫后在即刻（Ⅰ组）、第4天（Ⅱ组）、第14天（Ⅲ组）、第42天（Ⅳ组）四个时间点处死,各时间点设相应对照组,处死前36h惊厥组和对照组的大鼠腹腔注射BrdU。所有大鼠处死前均取血检测糖皮质激素。第Ⅳ组从P40开始进行Morris水迷宫试验。结果新生鼠3次发作后即刻和第4天与相应日龄对照组相比,齿状回BrdU阳性细胞数明显减少（P〈0．05）,而癫痫发作后14天和42天BrdU阳性细胞数增加,但发作后14天差异无统计学意义（P〉0．05）。在4天的Morris水迷宫试验中,匹罗卡品处理组大鼠到达平台的时间均长于对照组,但是只有第1天和第2天有统计学意义（P〈0．05）。检测结果表明高水平的糖皮质激素一直持续到发作后第4天,糖皮质激素水平与BrdU阳性细胞数呈负相关。结论新生大鼠反复痫性发作会造成早期神经发生减少,而后期神经发生增加;造成大鼠成年后认知功能缺陷;造成糖皮质激素水平增高,这与痫性大鼠形态学和行为学方面的改变有关。     

Repetitive noxious neonatal stimuli increases dentate gyrus cell proliferation and hippocampal brain‐derived neurotrophic factor levels

Neonatal noxious stimulation has been proposed to model pain triggered by diagnostic/therapeutic invasive procedures in premature infants. Previous studies have shown that hippocampal neurogenesis rate and the behavioral repertoire of adult rats may be altered by neonatal noxious stimuli. The purpose of this study was to evaluate whether noxious stimulation during neonatal period alters the nociceptive response and dentate gyrus neurogenesis when compared to rats subjected to a single noxious stimulus in late infancy. Plasma corticosterone and hippocampal brain‐derived neurotrophic factor (BDNF) levels were measured. Neurogenesis in the dentate gyrus was evaluated in adolescent rats (postnatal day 40; P40) exposed twice to intra‐plantar injections of Complete Freund's adjuvant (CFA) on P1 and P21 (group P1P21) or P8 and P21 (P8P21) or exposed once on P21 (pubertal). On P21, one subset of animals received 5‐bromo‐2′‐deoxyuridine (BrdU) and was euthanized on P40 for identification of proliferating cells in the dentate gyrus. Another subset was sampled for thermal response or plasma corticosterone measurement and hippocampal BDNF levels. Proliferative cell rate in dentate gyrus was the highest in all re‐exposed groups (P < 0.001), except for P8 females (P8P21F), revealing also a sex difference, where P8P21 males showed higher rate than females (P < 0.001). Stimulated groups took longer than CTL animals to lick the paws (P < 0.001), regardless of the age when the noxious stimulus was applied. Re‐exposed groups had lower corticosterone plasma level (P1P21 M and F, P8P21M) than controls. On the contrary, hippocampal BDNF was increased in males from both re‐exposed groups. These results show that infant noxious stimulation in neonatally previously stimulated rats is related to high proliferation in the DG and this association seems to be modified by the animal's sex. The new generated dentate granule cells in the hippocampus may have a role in the long‐term behavioral responses to neonatal nociceptive stimulation. Noxious stimulation in the neonatal period results in sex‐dependent neurogenic response. © 2013 Wiley Periodicals, Inc.     

新生期大鼠反复痫性发作的形态学及行为学结果与糖皮质激素水平升高有关(英文)

目的探讨新生期大鼠反复痫性发作后的形态学,行为学以及糖皮质激素水平的变化。方法64只出生后一天的Wistar大鼠随机分为惊厥组40只和对照组24只。惊厥组的新生鼠在出生后1天(P1)、4天(P4)、7天(P7)给予腹腔注射匹罗卡品,制备新生鼠癫痫模型;对照组的新生鼠腹腔注射生理盐水。惊厥组分别在第 3次致痫后在即刻(Ⅰ组)、第4 天(Ⅱ组)、第14 天(Ⅲ组)、第42天(Ⅳ组)四个时间点处死,各时间点设相应对照组,处死前36 h惊厥组和对照组的大鼠腹腔注射BrdU。所有大鼠处死前均取血检测糖皮质激素。第Ⅳ组从P40开始进行Morris水迷宫试验。结果新生鼠3次发作后即刻和第4天与相应日龄对照组相比,齿状回BrdU阳性细胞数明显减少(P<0.05),而癫痫发作后14天和42天BrdU阳性细胞数增加,但发作后14天差异无统计学意义(P>0.05)。在4天的Morris水迷宫试验中,匹罗卡品处理组大鼠到达平台的时间均长于对照组,但是只有第1天和第2天有统计学意义(P<0.05)。检测结果表明高水平的糖皮质激素一直持续到发作后第4天,糖皮质激素水平与BrdU阳性细胞数呈负相关。结论新生大鼠反复痫性发作会造成早期神经发生减少,而后期神经发生增加;造成大鼠成年后认知功能缺陷;造成糖皮质激素水平增高,这与痫性大鼠形态学和行为学方面的改变有关。     

Newly born dentate granule neurons after pilocarpine-induced epilepsy have hilar basal dendrites with immature synapses

Neurogenesis in the subgranular zone of the dentate gyrus persists throughout the lifespan of mammals, and the resulting newly born neurons are incorporated into existing hippocampal circuitry. Seizures increase the rate of neurogenesis in the adult rodent brain and result in granule cells in the dentate gyrus with basal dendrites. Using doublecortin (DCX) immunocytochemistry to label newly generated neurons the current study focuses on the electron microscopic features of DCX-labeled cell bodies and dendritic processes in the dentate gyrus of rats with pilocarpine-induced epilepsy. At the base of the granule cell layer clusters of cells that include up to six DCX-labeled cell bodies were observed. The cell bodies in these clusters lacked a one-to-one association with an astrocyte cell body and its processes, a relationship that is typical for newly born granule cells in control rats. Also, DCX-labeled basal dendrites in the hilus had immature synapses while those in control rats lacked synapses. These results indicate that increased neurogenesis after seizures alters the one-to-one relationship between astrocytes and DCX-labeled newly generated neurons at the base of the granule cell layer. The data also suggest that the synapses on DCX-labeled hilar basal dendrites contribute to the persistence of hilar basal dendrites on neurons born after pilocarpine-induced seizures.     

Effects of CXCR7-neutralizing antibody on neurogenesis in the hippocampal dentate gyrus and cognitive function in the chronic phase of cerebral ischemia

Stromal cell-derived factor-1 and its receptor CXCR4 are essential regulators of the neurogenesis that occurs in the adult hippocampal dentate gyrus.However,the effects of CXCR7,a new atypical receptor of stromal cell-derived factor-1,on hippocampal neurogenesis after a stroke remain largely unknown.Our study is the first to investigate the effect of a CXCR7-neutralizing antibody on neurogenesis in the dentate gyrus and the associated recovery of cognitive function of rats in the chronic stage of cerebral ischemia.The rats were randomly divided into sham,sham+anti-CXCR7,ischemia and ischemia+anti-CXCR7 groups.Endothelin-1 was injected in the ipsilateral motor cortex and striatum to induce focal cerebral ischemia.Sham group rats were injected with saline instead of endothelin-1 via intracranial injection.Both sham and ischemic rats were treated with intraventricular infusions of CXCR7-neutralizing antibodies for 6 days 1 week after surgery.Immunofluorescence staining with doublecortin,a marker for neuronal precursors,was performed to assess the neurogenesis in the dentate gyrus.We found that anti-CXCR7 antibody infusion enhanced the proliferation and dendritic development of doublecortin-labeled cells in the dentate gyrus in both ischemic and sham-operated rats.Spatial learning and memory functions were assessed by Morris water maze tests 30-32 days after ischemia.CXCR7-neutralizing antibody treatment significantly reduced the escape latency of the spatial navigation trial and increased the time spent in the target quadrant of spatial probe trial in animals that received ischemic insult,but not in sham operated rats.These results suggest that CXCR7-neutralizing antibody enhances the neurogenesis in the dentate gyrus and improves the cognitive function after cerebral ischemia in rats.All animal experimental protocols and procedures were approved by the Institutional Animal Care and Use Committee of China Medical University(CMU16089 R)on December 8,2016.     

Chronic temporal lobe epilepsy is associated with severely declined dentate neurogenesis in the adult hippocampus

While it is clear that acute hippocampal injury or status epilepticus increases the production of new neurons in the adult dentate gyrus (DG), the effects of chronic epilepsy on dentate neurogenesis are unknown. We hypothesize that epileptogenic changes and spontaneous recurrent motor seizures (SRMS) that ensue after hippocampal injury or status epilepticus considerably decrease dentate neurogenesis. We addressed this issue by quantifying the number of cells that are positive for doublecortin (DCX, a marker of new neurons) in the DG of adult F344 rats at 16 days and 5 months after an intracerebroventricular kainic acid (ICV KA) administration or after graded intraperitoneal KA (IP KA) injections, models of temporal lobe epilepsy (TLE). At early post-KA administration, the injured hippocampus exhibited increased dentate neurogenesis in both models. Conversely, at 5 months post-KA administration, the chronically epileptic hippocampus demonstrated severely declined neurogenesis, which was associated with considerable SRMS in both KA models. Additionally, stem/progenitor cell proliferation factors, FGF-2 and IGF-1, were decreased in the chronically epileptic hippocampus. Interestingly, the overall decrease in neurogenesis and the extent of SRMS were greater in rats receiving IP KA than rats receiving ICV KA, suggesting that the extent of neurogenesis during chronic TLE exhibits an inverse relationship with SRMS. These results provide novel evidence that chronic TLE is associated with extremely declined dentate neurogenesis. As fraction of newly born neurons become GABA-ergic interneurons, declined neurogenesis may contribute to the increased seizure-susceptibility of the DG in chronic TLE. Likewise, the hippocampal-dependent learning and memory deficits observed in chronic TLE could be linked at least partially to the declined neurogenesis.     

Chronic repetitive transcranial magnetic stimulation increases hippocampal neurogenesis in rats

Aim: While the underlying therapeutic mechanisms of repetitive transcranial magnetic stimulation (rTMS) treatment for depression remain unclear, recent animal studies have suggested that hippocampal neurogenesis might be required for the effects of antidepressant treatments including antidepressant drugs and electroconvulsive therapy. The aim of this study was to examine chronic rTMS effects on hippocampal neurogenesis in rats. Methods: Using a 70‐mm figure‐of‐eight coil, the stimulating parameters were set to 25 Hz and 70% of the rTMS device's maximum power. For 14 consecutive days, bromodeoxyuridine (BrdU) and 1000 pulses of rTMS were administered daily. Cell proliferation in the dentate gyrus was examined with immunohistochemistry. Results: In the rTMS‐treated group, BrdU‐positive cells were significantly increased in the dentate gyrus. Conclusion: Our results suggest that hippocampal neurogenesis might be involved in the antidepressant effects of chronic rTMS.