急性癫痫发作后海马齿状回颗粒细胞的树突改变

目的：为探讨癫痫发作敏感性的形成机制提供形态学依据。方法：海人酸(KA)或戊四氮(PTZ)诱导大鼠短暂癫痫发作后,用高尔基染色法对海马齿状回颗粒细胞的树突形态改变进行观察,并进行图像分析。结果：癫痫大鼠齿状回颗粒细胞树突的树突总长度、树突棘密度、树突分支点数和树突野最大伸展距离等均出现改变;除KA模型外,在PTZ模型中也得到了同样的证实。结论：一次癫痫发作后7d时,海马齿状回颗粒细胞(1)出现了明显增生改变,这可能是癫痫发作敏感性的原因之一;(2)出现的树突增生可能是各类癫痫模型的普遍性的变化。     

海人酸诱导成年大鼠颞叶癫痫中海马异常神经发生机制研究进展

神经发生(neurogenesis)是指神经干细胞(neural stem cells,NSCs)或神经前体细胞(neural precursor cells,NPCs)的增殖、分化以及新生神经元的存活、成熟和迁移整合的过程.实验证实~([1]),成年动物及人类的室管膜与室管膜下区、嗅球、海马、中隔、纹状体及皮质与脊髓广泛分布有多潜能的NSCs与NPCs,这些细胞能分化为有完整功能的神经元并整合入神经环路,提示中枢的神经发生不仅限于胚胎期,在生后乃至成年的整个发育期均能观察到神经发生.     

EphA4在海人酸诱导大鼠大脑皮层神经元凋亡中的表达及天麻素的影响

目的： 探讨EphA4在海人酸诱导大鼠大脑皮层神经元凋亡过程中的表达变化,及天麻素对EphA4表达的影响。方法：提取新生大鼠大脑皮层神经元体外培养,7 d后随机分为对照组、海人酸模型组、海人酸+天麻素干预组;采用倒置相差显微镜观察神经元形态学变化,Hoechst 33258荧光染色、AO/EB荧光染色、LDH活性测定检测神经元凋亡和坏死情况,CY3荧光染色检测EphA4表达变化。结果：海人酸模型组较对照组神经元凋亡率显著升高（P<0.01）,EphA4表达显著增高（P<0.01）;海人酸+天麻素干预组较海人酸模型组神经元凋亡率显著下降,EphA4表达上调显著受抑。结论：海人酸诱导大鼠大脑皮层神经元凋亡过程中EphA4表达增高,天麻素在这一过程中抑制EphA4表达,对神经元具有一定保护作用。     

海人酸对神经干细胞增殖及分化的影响

背景：神经干细胞对脑组织的修复作用非常有限,约80%新增殖的内源性神经干细胞在6周内死亡,仅0.2%的细胞继续增殖、分化,参与修复。 目的：分析不同剂量海人酸在对神经干细胞增殖及分化的影响。 方法：体外分离并培养新生Wistar大鼠神经干细胞,将神经干细胞分为空白对照组和加入不同浓度梯度的海人酸组,通过免疫组化法和免疫荧光法进行鉴定,MTT比色法测定海人酸对神经干细胞分化的影响,计算分化后神经元和星形胶质细胞比例。 结果与结论：海人酸组贴壁的神经球分化速度较空白对照组快,在同一时间点进行观察,神经细胞的迁移距离较未处理组远。分化5 d后,海人酸组所分化的细胞中,星状细胞较空白对照组多,而神经元样细胞相对较少,培养的细胞具有自我更新和向神经元﹑少突胶质细胞和星形胶质细胞分化的潜能。兴奋性氨基酸海人酸可使部分神经干细胞死亡,但可促进幸存的神经干细胞增殖及分化,并诱导其向星形胶质细胞分化。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

T细胞转录因子-4在大鼠脑缺血再灌注海马齿状回神经干细胞中的表达

目的:检测T细胞转录因子-4(Tcf-4)在大鼠脑缺血再灌注海马组织神经干细胞中的表达及其变化。探讨影响神经干细胞早期增殖分化的分子调控机制。方法:采用大脑中动脉栓塞(MCAO)制作大鼠脑缺血再灌注模型。用免疫组织化学SP法及RT-PCR法检测海马神经干细胞BrdU、Tcf-4中的表达。结果:随着脑缺血再灌注第3日齿状回神经元BrdU阳性细胞明显增多,第7日达高峰,然后逐渐减少。Tcf-4 mRNA反应产物随脑缺血再灌注时间延长逐渐增多,第21日表达最强,以后表达逐渐减少。结论:Tcf-4时间依赖性表达与神经干细胞增殖分化进程相吻合,说明其在神经干细胞晚期分化中起重要调控作用。     

青春期大鼠癫痫发作后海马齿状回颗粒细胞层神经细胞增殖的改变

目的:探讨青春期大鼠癫痫发作后海马齿状回颗粒细胞层神经细胞数量的变化。方法:选择健康4周龄雄性SD大鼠,应用氯化锂-匹罗卡品药物点燃造模,造模成功后根据取脑组织时间分为24 h组、2周组、4周组,并设相应的对照组。溴脱氧尿嘧啶核苷(BrdU)标记后免疫荧光染色,用激光共聚焦观察大鼠海马齿状回(DG)颗粒细胞层BrdU阳性细胞。结果:24 h和2周实验组BrdU阳性细胞显著增多,分别较对照组增加55.1%和39.6%,2周实验组比24 h实验组降低15.5%(P<0.05);4周实验组BrdU阳性细胞数较对照组无明显差异(P>0.05)。结论:青春期大鼠癫痫发作可引起海马齿状回颗粒层神经细胞增殖的升高,但随着时间的延长有下降的趋势,至4周左右神经细胞的增殖趋于正常。     

中药龟板对Parkinson病大鼠模型BMP4表达的影响

为研究益肾中药龟板对Parkinson病(PD)模型大鼠骨形成蛋白4(BMP4)表达的影响,本研究将6-羟基多巴胺注入大鼠黑质建立PD大鼠模型,对模型大鼠行高、低剂量龟板水煎液口服治疗45d后,采用ELISA和RT-PCR方法进行血清中BMP4酶联免疫试验和脑黑质、纹状体中BMP4mRNA的检测。结果显示:PD模型组的BMP4表达明显降低,用龟板治疗后可以显著阻碍此趋势,而且高剂量组比低剂量组效果更为明显(P<0.05)。本研究结果提示,龟板有明显的促进BMP4及BMP4mRNA表达的作用。     

骨形成蛋白4对人胶质瘤干细胞增殖和凋亡的影响

目的 研究骨形成蛋白4(bone morphogenetic protein 4,BMP4)对人胶质瘤干细胞增殖和凋亡的影响.方法 在体外以重组人BMP4蛋白干预人胶质瘤U87细胞系来源的胶质瘤干细胞,免疫荧光鉴定胶质瘤干细胞,通过软琼脂克隆实验、流式细胞仪检测,观察BMP4对胶质瘤干细胞增殖和凋亡的影响.结果 BMP4能显著抑制胶质瘤干细胞的增殖能力,并诱导其凋亡.BMP4组增殖相关蛋白Cyclin D1 表达降低,抗凋亡蛋白Bcl-2表达明显降低,促凋亡蛋白Bax表达显著增多.结论 BMP4可显著抑制胶质瘤U87细胞系来源的胶质瘤干细胞的增殖能力,并诱导其凋亡.     

脊髓损伤模型大鼠神经胶质细胞增殖与胶质纤维酸性蛋白的表达

背景：星形胶质细胞可以通过细胞裂解释放各种神经营养因子,并可促进损伤脊髓的修复。 目的：观察脊髓损伤模型大鼠神经胶质纤维酸性蛋白的表达及对其后肢功能恢复的影响。 方法：将SD大鼠采用Allen's法撞击T9~10节段致脊髓损伤,造模成功后蛛网膜下腔移植骨形态发生蛋白7,并设置仅蛛网膜下腔移植His蛋白的正常SD大鼠做对照。用BBB评分法评估两组大鼠后肢的运动功能,用免疫组织化学染色法和Western-blot法观察各组神经胶质纤维酸性蛋白的表达。 结果与结论：BBB评分结果显示,模型组大鼠脊髓损伤后下肢功能自行恢复率达68%。模型组脊髓损伤3和7 d,损伤区域神经胶质纤维酸性蛋白表达逐渐增加(P  < 0.05),随后逐渐下降,于脊髓损伤28 d后逐渐恢复到对照组水平(P > 0.05)。脊髓损伤后1~14 d两组胶质纤维酸性蛋白表达逐渐升高(P > 0.05)。结果证实,脊髓损伤后蛛网膜下腔移植骨形态发生蛋白7可诱导星形胶质细胞增殖,神经胶质纤维酸性蛋白的表达增强,进而促进脊髓损伤大鼠后肢功能的恢复。     

BMP4沉默对骨肉瘤细胞系MG-63上皮间质转换及侵袭转移能力的影响

目的探讨沉默骨形成蛋白-4(BMP4)对骨肉瘤细胞系MG-63上皮间质转换(EMT)和侵袭迁移能力的影响。方法脂质体法转染MG-63细胞BMP4 shRNA表达质粒,将MG-63细胞分为MG-63对照组(正常培养对照)、空白对照组(转染空白质粒)和BMP4沉默组(转染BMP4 shRNA质粒)。反转录聚合酶链反应(RT-PCR)法和Western blot检测细胞E-cadherin、vimentin、twist和snail的mRNA及蛋白水平。Transwell侵袭实验和伤口愈合实验检测细胞侵袭和迁移能力。结果沉默BMP4后MG-63细胞的间质细胞标志物vimentin、twist1和snail水平降低,上皮细胞标志物E-cadherin表达增高(P0.05)。BMP4沉默组细胞穿膜细胞数和迁移距离显著少于MG-63对照组和空白对照组(P0.05)。结论沉默BMP4基因可以使间质型MG-63骨肉瘤细胞向上皮细胞表型转变,从而有效地降低肿瘤细胞的侵袭迁移能力。     

Transplantation of cultured astrocytes attenuates degenerative changes in rats with kainic acid-induced brain damage

Viability of astrocyte grafts introduced into CA1 pyramidal layer of the left dorsal hippocampus after injection of kainic acid into this brain region and the effects of these grafts on the hippocampus and amygdala were studied on Wistar rats. In rats with astrocyte grafts the degree of destruction in fields CA1-CA2 of the dorsal and ventral hippocampus, fields CA3-CA4 of the ventral hippocampus, and central and basolateral amygdala was lower compared to animals with kainic acid-induced hippocampal damage and control rats; destructions in the dentate fascia were absent. Our results suggest that astrocyte grafts stimulate neurogenesis in the mature brain of recipient rats with kainic acid-induced brain damage. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 140, No. 12, pp. 627–632, December, 2005     

海人酸致癫痫大鼠海马结构中noggin表达变化

目的:研究海人酸(kainic acid,KA)侧脑室注射并诱发癫痫持续状态(status epilepticus,SE)后大鼠海马结构中noggin基因在大鼠海马的表达变化。方法:大鼠在侧脑室注射KA后1、3、7、14、30和60d等不同时间,采用RT-PCR研究noggin mRNA含量变化,采用免疫组化观察noggin蛋白表达变化。结果:在正常大鼠海马结构中noggin mRNA有少量表达。noggin阳性细胞主要位于齿状回及CA3、CA1区,数量较少。侧脑室注射KA诱发SE后,noggin表达持续升高,3d达到高峰;7d在脑内的表达开始降低;注射后2个月,noggin表达降至术前水平,仅见散在的阳性细胞。结论:侧脑室注射KA并诱发SE后,大鼠海马结构中noggin表达明显增加。     

Chronic high corticosterone reduces neurogenesis in the dentate gyrus of adult male and female rats

Adult neurogenesis in the dentate gyrus of the hippocampus is altered with stress exposure and has been implicated in depression. High levels of corticosterone (CORT) suppress neurogenesis in the dentate gyrus of male rats. However both acute and chronic stress do not consistently reduce adult hippocampal neurogenesis in female rats. Therefore, this study was conducted to investigate the effect of different doses of corticosterone on hippocampal neurogenesis in male and female rats. Rats received 21 days of s.c. injections of either oil, 10 or 40 mg/kg CORT. Subjects were perfused 24 h after the last CORT injection and brains were analyzed for cell proliferation (Ki67-labeling) or immature neurons (doublecortin-labeling). Results show that in both males and females high CORT, but not low CORT, reduced both cell proliferation and the density of immature neurons in the dentate gyrus. Furthermore, high CORT males had reduced density in immature neurons in both the ventral and dorsal regions while high CORT females only showed the reduced density of immature neurons in the ventral hippocampus. The high dose of CORT disrupted the estrous cycle of females. Further, the low dose of CORT significantly reduced weight gain and increased basal CORT levels in males but not females, suggesting a greater vulnerability in males with the lower dose of CORT. Thus we find subtle sex differences in the response to chronic CORT on both body weight and on neurogenesis in the dorsal dentate gyrus that may play a role in understanding different vulnerabilities to stress-related neuropsychiatric disorders between the sexes.     

Chronic treatment of exendin-4 affects cell proliferation and neuroblast differentiation in the adult mouse hippocampal dentate gyrus

Exendin-4 isolated from Heloderma suspectum venom acts via glucagon-like peptide 1 (GLP-1) receptor and has clinically been used in the type 2 diabetes. In this study, we investigated the effects of exendin-4 on cell proliferation and neuroblast differentiation in the subgranular zone (SGZ) of the dentate gyrus in mice. Exendin-4 was treated intraperitoneally to male ICR mice twice a day for 21 days. The exendin-4-treated group showed a significantly higher number of Ki67- (1.51-fold), doublecortin (DCX)- (2.5-fold) and 5-bromo-2′-deoxyuridine (BrdU) + DCX- (2.46-fold) immunoreactive cells in the SGZ of the dentate gyrus compared to the control group. The results of this study showed that treatment with exendin-4 increased cell proliferation neuroblast differentiation in the SGZ of the dentate gyrus, suggesting that exendin-4 promotes structural plasticity in the dentate gyrus.     

体外骨形态发生蛋白4抑制乳腺癌细胞的增殖和迁移

目的:研究骨形态发生蛋白4(BMP4)对乳腺癌细胞MCF-7增殖、迁移和侵袭能力的影响.方法:将重组慢病毒Lv-BMP4及干扰慢病毒Lv-shBMP4感染MCF-7细胞,构建MCF-7/Lv-BMP4过表达组及MCF-7/Lv-shBMP4干扰实验组,同时设空白组(Blank)、慢病毒空载对照组(Lv-NC)、 过表达...     

GABAA receptor subunits in the rat hippocampus II: Altered distribution in kainic acid-induced temporal lobe epilepsy

Intraperitoneal injection of kainic acid in the rat represents a widely used animal model of human temporal lobe epilepsy. Injection of kainic acid induces acute limbic seizures which are accompanied by seizure-induced brain damage and late spontaneous recurrent seizures. There is considerable evidence for an altered transmission of GABA in human temporal lobe epilepsy and in the kainic acid model. We therefore investigated by immunocytochemistry the distribution of 13 GABA receptor subunits in the hippocampus of rats 12 h, 24 h, and two, seven and 30 days after injection of kainic acid. Within the molecular layer of the dentate gyrus, decreases in α₂- and δ- and slight increases in α₁-, β₂- and β₃-immunoreactivities were observed at early intervals (12 to 24 h) after kainic acid injection. These changes were succeeded by marked increases in α₁-, α₂-, α₄-, α₅-, β₁-, β₃-, γ₂- and δ-immunoreactivities in the same area after seven to 30 days. Within the hippocampus proper, changes in expression of GABA_A receptor subunits were demarcated by considerable neurodegeneration of CA1 and CA3 pyramidal neurons. All subunits present within dendritic areas of CA1 and CA3 were affected. These were α₁, α₂, α₅, β₁–β₃, γ₂ and α₄ (present only in CA1). Decreases in these subunits were followed by increased expression of α₂-, α₅-, β₃-, γ₂- and δ-subunits in the hippocampus proper notably in CA3 at later intervals (up to 30 days). α₁-, β₂-, γ₂- and δ-subunits were found in presumed GABA containing interneurons throughout the hippocampus. Their immunoreactivity was augmented after two to seven days. Some α₄-, γ₃- and δ-immunoreactivity was also found in astrocytes 48 h after kainic acid injection.Our data indicate an impairment of GABA-mediated neurotransmission due to a lasting loss of GABA_A receptor containing cells after kainic acid-induced seizures. The seizure-induced loss in GABA_A receptors within the hippocampus may in part be compensated by increased expression of GABA_A receptor subunits within the molecular layer of the dentate gyrus and in pyramidal cells.     

Both estrogen receptor alpha and estrogen receptor beta agonists enhance cell proliferation in the dentate gyrus of adult female rats

This study investigated the involvement of estrogen receptors alpha and beta in estradiol-induced enhancement of hippocampal neurogenesis in the adult female rat. Subtype selective estrogen receptor agonists, propyl-pyrazole triol (estrogen receptor alpha agonist) and diarylpropionitrile (estrogen receptor beta agonist) were examined for each receptor's contribution, individual and cooperative, for estradiol-enhanced hippocampal cell proliferation. Estradiol increases hippocampal cell proliferation within 4 h [Ormerod BK, Lee TT, Galea LA (2003) Estradiol initially enhances but subsequently suppresses (via adrenal steroids) granule cell proliferation in the dentate gyrus of adult female rats. J Neurobiol 55:247-260]. Therefore, animals received s.c. injections of estradiol (10 microg), propyl-pyrazole triol and diarylpropionitrile alone (1.25, 2.5, 5.0 mg/0.1 ml dimethylsulfoxide) or in combination (2.5 mg propyl-pyrazole triol+2.5 mg diarylpropionitrile/0.1 ml dimethylsulfoxide) and 4 h later received an i.p. injection of the cell synthesis marker, bromodeoxyuridine (200 mg/kg). Diarylpropionitrile enhanced cell proliferation at all three administered doses (1.25 mg, P<0.008; 2.5 mg, P<0.003; 5 mg, P<0.005), whereas propyl-pyrazole triol significantly increased cell proliferation (P<0.0002) only at the dose of 2.5 mg. Our results demonstrate both estrogen receptor alpha and estrogen receptor beta are individually involved in estradiol-enhanced cell proliferation. Furthermore both estrogen receptor alpha and estrogen receptor beta mRNA was found co-localized with Ki-67 expression in the hippocampus albeit at low levels, indicating a potential direct influence of each receptor subtype on progenitor cells and their progeny. Dual receptor activation resulted in reduced levels of cell proliferation, supporting previous studies suggesting that estrogen receptor alpha and estrogen receptor beta may modulate each other's activity. Our results also suggest that a component of estrogen receptor-regulated cell proliferation may take place through alternative ligand and/or cell-signaling mechanisms.