重组大鼠质粒pEGFP-GDNF的构建和在脊髓内表达的实验研究

采用RT PCR方法从大鼠胎脑组织总RNA中扩增出该基因的全序列cDNA ,并以融合蛋白方式克隆到增强型绿色荧光蛋白 (EGFP)报告基因的真核表达载体中 ,成功构建了重组质粒 pEGFP GDNF在体表达载体。采用基因注射法将阳离子脂质体DC Chol和pEGFP GDNF基因混合后转染至大鼠胸段脊髓组织中 ,观察GDNF在大鼠脊髓中的表达。RT PCR结果表明注射局部GDNFmRNA表达增加。荧光显微镜下观察发现 ,注射局部灰质和白质神经细胞内均有较多绿色荧光蛋白表达。本研究结果提示 ,阳离子脂质体介导GDNF体内转基因的方法是可行的 ,EGFP可作为报告基因观察GDNF在体内的表达。     

重组大鼠质粒pEGFP—GDNF的构建和脊髓内表达的实验研究

采用RT－PCR方法从大鼠胎脑组织总RNA中扩增出该基因的全序列cDNA,并以融合蛋白方式克隆到增强型绿色荧光蛋白（EGFP）报告基因的真核表达载体中,成功构建了重组质粒pEGFP-GDNF在体表达载体。采用基因注射法将阳离子脂质体DC－Chol和pEGFP-GDNF基因混合后转染至大鼠胸段脊髓组织中,观察GDNF在大鼠脊髓中的表达。RT－PCR结果表明注射局部GDNF mRNA表达增加。荧光显微镜下观察发现,注射局部灰质和白质神经细胞内均有较多绿色荧光蛋白表达。本研究结果提示,阳离子脂质体介导GDNF体内转基因的方法是可行的,EGFP可作为报告基因观察GDNF在体内的表达。     

Rapsyn重组质粒转染小鼠骨髓间充质干细胞

目的探讨采用脂质体介导的基因转移技术将重组pEGFP-N1/Rapsyn质粒转染至小鼠骨髓间充质干细胞(BMSCs)的可能性,并观察Rapsyn蛋白在靶细胞中的表达。方法采用全骨髓贴壁培养法分离纯化C57BL/6小鼠的BMSCs,在体外进行扩增、传代。取第3代细胞,采用脂质体介导的基因转移技术将重组pEGFP-N1/Rapsyn质粒转染至BMSCs中,并置荧光显微镜下观察转染结果;采用Western blot法检测靶细胞中Rapsyn蛋白的表达。结果 BMSCs经转染后24h可在荧光显微镜下观察到绿色荧光,转染pEGFP-N1/Rapsyn质粒的BMSCs可稳定表达Rapsyn蛋白。结论利用脂质体介导法可将Rapsyn基因转染至BMSCs中,并能稳定表达Rapsyn蛋白。     

NOV基因真核表达载体的构建及在大鼠真皮多能干细胞中的表达

目的 构建肾母细胞瘤过度表达(NOV)基因真核表达载体并检测其在真皮多能干细胞中的表达. 方法 利用逆转录-多聚酶链反应(RT-PCR)方法,以新生大鼠大脑组织总RNA为模板,扩增出1 178bp的NOV基因的cDNA编码区序列,然后用Hind Ⅲ和BamH Ⅰ双酶切后定向克隆入真核表达载体pEGFP-N1质粒中,用脂质体法将重组质粒转染入大鼠真皮多能干细胞中,荧光显微镜观察转染产物,RT-PCR法检测转染细胞中NOV基因表达. 结果 NOV基因cDNA正确克隆到真核表达载体pEGFP-N1质粒中;重组质粒体外转染入大鼠真皮多能干细胞后,可见转染细胞有绿色荧光表达.转染细胞中检测到NOV基因. 结论 构建成功NOV基因重组质粒,并能在大鼠真皮多能干细胞中稳定表达,为NOV基因及真皮多能干细胞的作用研究提供了有利的分子工具.     

骨髓间充质干细胞表达的hVEGF121/EGFP融合蛋白的提纯及功能鉴定**

目的：用hVEGF121/EGFP真核质粒转染骨髓间充质干细胞,提纯其表达的hVEGF121/EGFP融合蛋白,并体外检测其功能。 方法：用课题组前期工作构建的pEGFP-N2-hVEGF121重组质粒提取质粒DNA。通过阳离子脂质体介导pEGFP-N2-hVEGF121重组质粒DNA转染体外培养的骨髓间充质干细胞,使用荧光显微镜检测hVEGF121/EGFP融合蛋白表达。用Amicon超滤离心管纯化融合蛋白。 结果：荧光显微镜下观察到转染pEGFP-N2-hVEGF121重组质粒的骨髓间充质干细胞,Westen blot证实转染骨髓间充质干细胞的培养液中存在hVEGF121/EGFP融合蛋白表达。MTT试验证实人脐静脉内皮细胞数量在hVEGF121/EGFP融合蛋白组明显多于对照组(P < 0.05)。Miles实验证实hVEGF121/EGFP融合蛋白增加血管壁的通透性。 结论：①携带hVEGF121/EGFP融合蛋白表达基因的真核表达质粒,在骨髓间充质干细胞中获得表达。②骨髓间充质干细胞表达的hVEGF121/EGFP融合蛋白在体外具有野生型血管内皮细胞生长因子的功能。     

重组pEGFP-N1-IGF-1质粒体内转染骨质疏松大鼠的可行性

背景：胰岛素样生长因子1水平的下降与骨质疏松密切相关,目前应用基因技术是骨质疏松等骨代谢疾病治疗的发展方向,但病毒载体可能引起严重免疫反应,质粒重组体pEGFP-N1-IGF-1活体转染骨质疏松大鼠可能成为一种有效的治疗手段。 目的：观察质粒重组体pEGFP-N1-IGF-1转染骨质疏松大鼠中胰岛素样生长因子1的表达。 方法：雌性SD大鼠随机分为假手术组、pEGFP-N1组和pEGFP-N1-IGF-1组。后2组予双侧卵巢切除。术后12周,3组依次给予生理盐水、pEGFP-N1载体和质粒重组体pEGFP-N1-IGF-1分别复合脂质体转染。转染后48 h荧光活体成像及肝脏切片观察,定期测定血清胰岛素样生长因子1质量浓度。 结果与结论：转染后pEGFP-N1组和pEGFP-N1-IGF-1组大鼠均可见全身大部出现明显荧光表达,以肝脏及尾部为著,肝脏切片镜下观察可见明显荧光表达。去卵巢大鼠血清胰岛素样生长因子1质量浓度显著降低(P < 0.05);pEGFP-N1-IGF-1转染使去卵巢大鼠血清胰岛素样生长因子1质量浓度明显升高(P < 0.05),而后随时间延长而逐渐降低(P < 0.05)。结果证明质粒重组体pEGFP-N1-IGF-1能够在骨质疏松大鼠体内成功转染并表达胰岛素样生长因子1蛋白,为应用胰岛素样生长因子1基因治疗骨质疏松症提供了理论基础。     

pIRES2-EGFP-gAd质粒载体构建及在大鼠肾脏的表达

背景：已有研究证实经腹腔注射基因转染肾脏是一种简便有效的实验方法。 目的：构建表达球形脂联素(gAd)的pIRES2-EGFP-gAd质粒,观察其在大鼠肾脏的表达。 方法：以pET/gAd 质粒为模板,PCR扩增目的片段,转化大肠杆菌,用EcoRⅠBamHⅠ双酶切后,与pIRES2-EGFP荧光质粒连接,重组构建pIRES2-EGFP-gAd质粒。将构建成功的pIRES2-EGFP-gAd质粒采用脂质体介导经腹腔注射正常大鼠体内,于注射24,48,96 h和7 d留取肾脏标本进行冰冻切片,荧光显微镜下观察绿色荧光蛋白在肾组织中的表达,同时采用Western bot检测肾组织绿色荧光蛋白的表达。 结果与结论：重组构建的pIRES2-EGFP-gAd载体经双酶切电泳分析及DNA测序证实无碱基突变。在腹腔注射脂质体/ pIRES2-EGFP-gAd转染复合物24 h,即可在肾小球肾间质检测到绿色荧光,注射48 h,荧光进一步增强,之后逐渐减弱,至注射7 d时,荧光强度明显减弱。Western bot检测的绿色荧光蛋白的表达结果与冰冻组织切片结果一致。说明脂质体能够介导pIRES2-EGFP-gAd真核载体在大鼠肾脏表达。     

野生型Ⅱ型神经纤维瘤病基因Ⅱ亚型真核表达载体的构建及其功能

目的构建野生型Ⅱ型神经纤维瘤病基因（NF2）Ⅱ亚型的真核表达载体，观察其在人胚胎肾细胞293（HEK293）中的表达并检测其转染神经鞘瘤细胞（RT4）后的功能。方法以人胎脑cDNA文库中的NF2Ⅱ亚型基因为模板．应用聚合酶链反应技术扩增野生型NF2Ⅱ亚型基因，并定向克隆至真核表达载体pEGFP-N1质粒中：经鉴定正确的重组质粒pEGFP-NF2Ⅱ亚型，用Lipofectamine2000脂质体导人人胚胎肾细胞293，通过荧光显微镜和Western Blotting法观察基因表达水平：随后转染大鼠神经鞘瘤细胞．利用水溶性四氮唑法观察野生型NF2Ⅱ亚型基因对大鼠神经鞘瘤细胞增殖的影响。结果经序列分析证实，克隆的NF2Ⅱ亚型基因与Genebank中的序列完全一致。DNA琼脂糖凝胶电泳检测显示，经双酶切后的质粒pEGFPcDNA片段大小约为4700bp：NF2Ⅱ亚型基因cDNA片段大小为l770bp，NF2Ⅱ亚型基因的真核表达载体可瞬时转染人胚胎肾细胞293，通过荧光显微镜和Westem Blotting方法得到证实；水溶性四氮唑法检测显示，转染pEGFP-NF2Ⅱ亚型并表达NF2Ⅱ亚型编码蛋白的293细胞与对照组293细胞的增殖指数相同。结论所构建的野生型NF2Ⅱ亚型基因真核表达载体可在人胚胎肾细胞293中表达，且不具有抑制肿瘤细胞增殖的特性。     

重组人白细胞介素1受体拮抗蛋白荧光质粒在软骨细胞的表达**☆

背景：白细胞介素1受体拮抗蛋白能延缓骨性关节炎进程,通过转基因方法可以使白细胞介素1受体拮抗蛋白表达的增加。 目的：观察重组人重组人白细胞介素1受体拮抗蛋白荧光质粒的构建及经脂质体转染软骨细胞的表达情况。 方法：双酶切法切取重组人白细胞介素1受体拮抗蛋白的c-DNA片段,通过T4DNA连接酶连接到pEGFP-C1载体上。体外分离培养兔关节软骨细胞,然后用构建的重组人白细胞介素1受体拮抗蛋白质粒经脂质体转染软骨细胞,通过荧光显微镜观察转基因的表达和荧光定量PCR检测其表达。 结果与结论：获得重组人pEGFP-C1-IL-1Ra真核表达载体质粒,酶切及测序结果证明表达质粒的DNA序列完全正确。荧光显微镜观察有绿色荧光蛋白表达,荧光定量PCR鉴定证实转染的软骨细胞基因得到表达。     

改良的三维脑片培养模型研究脑胶质瘤细胞的迁移及侵袭

目的 建立一种新型的体外三维脑片共培养模型,观察绿色荧光蛋白转染的大鼠C6细胞在脑片模型上的侵袭、迁移形式,模拟胶质瘤细胞在脑内播散的方式. 方法 脂质体介导pEGFP-N3质粒转染体外常规培养的C6胶质瘤细胞,筛选稳定表达绿色荧光蛋白的细胞,荧光显微镜和流式细胞仪分别观察和计数绿色荧光蛋白的表达;活体取3周龄SD大鼠全脑,制作400 μm厚脑片并培养于Millicell插入式细胞培养皿.碘化丙啶(PD染色鉴定脑片神经元活性;将转染后的绿色荧光细胞C6细胞球接种于脑片表面,形成胶质瘤细胞-脑片共培养模型.荧光显微镜及激光共聚焦显微镜观察C6细胞在脑片上的侵袭和迁移. 结果 荧光显微镜及流式细胞仪检测转染后C6细胞几乎全部表达绿色荧光蛋白;脑片培养7d后仍然保持完整的皮质、尾状核、胼胝体等组织结构.PI染色证实脑片中神经元保持活性;荧光显微镜下观察显示C6细胞接种脑片表面1、3、5、7d后,迁移范围随时间的增加而逐渐增加;激光共聚焦逐层扫描可见C6细胞在脑片中的侵袭及三维分布,侵袭过程中C6细胞形态保持良好. 结论 大鼠脑片培养及肿瘤细胞-脑片共培养模型是研究胶质瘤细胞在体内的侵袭、迁移形式以及抗肿瘤治疗的潜在模型.     

Development of the projection from the nucleus of the brachium of the inferior colliculus to the superior colliculus in the ferret

Neurons in the deeper layers of the superior colliculus (SC) have spatially tuned receptive fields that are arranged to form a map of auditory space. The spatial tuning of these neurons emerges gradually in an experience-dependent manner after the onset of hearing, but the relative contributions of peripheral and central factors in this process of maturation are unknown. We have studied the postnatal development of the projection to the ferret SC from the nucleus of the brachium of the inferior colliculus (nBIC), its main source of auditory input, to determine whether the emergence of auditory map topography can be attributed to anatomical rewiring of this projection. The pattern of retrograde labeling produced by injections of fluorescent microspheres in the SC on postnatal day (P) 0 and just after the age of hearing onset (P29), showed that the nBIC-SC projection is topographically organized in the rostrocaudal axis, along which sound azimuth is represented, from birth. Injections of biotinylated dextran amine-fluorescein into the nBIC at different ages (P30, 60, and 90) labeled axons with numerous terminals and en passant boutons throughout the deeper layers of the SC. This labeling covered the entire mediolateral extent of the SC, but, in keeping with the pattern of retrograde labeling following microsphere injections in the SC, was more restricted rostrocaudally. No systematic changes were observed with age. The stability of the nBIC-SC projection over this period suggests that developmental changes in auditory spatial tuning involve other processes, rather than a gross refinement of the projection from the nBIC.     

The organization of the connections between the cortex and the claustrum in the monkey

The distribution of labelled cells and of extracellular granules in the claustrum has been studied after injections of horseradish peroxidase in several areas of the neocortex. The frontal and parietal lobes are related to the anterior and posterior halves respectively of the claustrum, and the occipital and temporal cortex to the posterior and inferior margins. Parts of the claustrum related to areas of the cortex in the frontal lobe overlap considerably in the antero-posterior dimension with parts related to widely separated but interconnected areas of the parieto-temporal cortex. Areas of cortex within one lobe which are interconnected are related to parts of the claustrum which overlap in the dorsoventral dimension.     

Sexual pheromones and the evolution of the reward system of the brain: the chemosensory function of the amygdala

The amygdala of all tetrapod vertebrates receives direct projections from the main and accessory olfactory bulbs, and the strong similarities in the organization of these projections suggest that they have undergone a very conservative evolution. However, current ideas about the function of the amygdala do not pay sufficient attention to its chemosensory role, but only view it as the core of the emotional brain. In this study, we propose that both roles of the amygdala are intimately linked since the amygdala is actually involved in mediating emotional responses to chemical signals. The amygdala is the only structure in the brain receiving pheromonal information directly from the accessory olfactory bulbs and we have shown in mice that males emit sexual pheromones that are innately attractive for females. In fact, sexual pheromones can be used as unconditioned stimuli to induce a conditioned attraction to previously neutral odorants as well as a conditioned place preference. Therefore, sexual pheromones should be regarded as natural reinforcers. Behavioural and pharmacological studies (reviewed here) have shown that the females' innate preference for sexual pheromones is not affected by lesions of the dopaminergic cells of the ventral tegmental area, and that the systemic administration of dopamine antagonists do not alter neither the attraction nor the reinforcing effects of these pheromones. Anatomical studies have shown that the vomeronasal amygdala gives rise to important projections to the olfactory tubercle and the islands of Calleja, suggesting that these amygdalo-striatal pathways might be involved in the reinforcing value of sexual pheromones.     

Evidence for the collateral innervation of the esophagus and the heart from neurons in the compact formation of the nucleus ambiguus of the rat

We investigated whether the heart receives collateral projections from the neurons which innervate the esophagus with a retrograde double-labeling method using two fluorescent tracers. Following injections of True Blue (TB) into the esophagus and Diamidino Yellow (DY) into the heart, about 21.9% of the labeled esophageal motoneurons in the compact formation of the nucleus ambiguus (AmC) were retrogradely double labeled. No single-labeled cardiac motoneurons were found in the AmC. The present results provide anatomical substrates for the esophagocardiac reflex.     

A projection to the striatum from the medial subdivision of the posterior group of the thalamus in the cat

Injections of wheat germ agglutinin-conjugated horseradish peroxidase in the lateral part of the caudate nucleus or the putamen of the cat result in retrograde thalamic cell-labeling in the rostral extension of the medial subdivision of the posterior group (POM). Autoradiography after [³H]amino acid injection of POM reveals a dense and discontinuous distribution of axons in the lateral half of the caudate and putamen concentrated at their middle rostrocaudal levels. This newly discovered thalamostriatal projection of POM may account for somatosensory activity observed in striatal cells.     

Role of the paraventricular nucleus in the projection from the nucleus of the solitary tract to the olfactory bulb

Electrophysiological experiments were performed on anesthetized rats to determine the effects of lesions of the paraventricular nucleus on the amplitude of evoked potentials recorded in the periglomerular layer of the olfactory bulb after nucleus of the solitary tract electrical stimulation. Lesions of the paraventricular nucleus enhance the amplitude of both the positive and negative components of the evoked potential in the olfactory bulb. The pathway from the paraventricular nucleus to the olfactory bulb seems to exert a suppressive influence over the projection from the nucleus of the solitary tract to the olfactory bulb under these conditions.     

Projections from the five divisions of the orbital cortex to the thalamus in the rat

The orbital cortex (ORB) of the rat consists of five divisions: the medial (MO), ventral (VO), ventrolateral (VLO), lateral (LO), and dorsolateral (DLO) orbital cortices. No previous report has comprehensively examined and compared projections from each division of the ORB to the thalamus. Using the anterograde anatomical tracer, Phaseolus vulgaris leucoagglutinin, we describe the efferent projections from the five divisions of the ORB to the thalamus in the rat. We demonstrated that, with some overlap, each division of the ORB distributed in a distinct (and unique) manner to nuclei of the thalamus. Overall, ORB projected to a relatively restricted number of sites in the thalamus, and strikingly distributed entirely to structures of the medial/midline thalamus, while completely avoiding lateral regions or principal nuclei of the thalamus. The main termination sites in the thalamus were the paratenial nucleus (PT) and nucleus reuniens (RE) of the midline thalamus, the medial (MDm) and central (MDc) divisions of the mediodorsal nucleus, the intermediodorsal nucleus, the central lateral, paracentral, and central medial nuclei of the rostral intralaminar complex and the submedial nucleus (SM). With some exceptions, medial divisions of the ORB (MO, VO) mainly targeted “limbic-associated” nuclei such as PT, RE, and MDm, whereas lateral division (VLO, LO, DLO) primarily distributed to “sensorimotor-associated” nuclei including MDc, SM, and the rostral intralaminar complex. As discussed herein, the medial/midline thalamus may represent an important link (or bridge) between the orbital cortex and the hippocampus and between the ORB and medial prefrontal cortex. In summary, the present results demonstrate that each division of the orbital cortex projects in a distinct manner to nuclei of the thalamus which suggests unique functions for each division of the orbital cortex.     

On the development of the stratification of the inner plexiform layer in the chick retina

This study investigated the development of the subdivision of the chick inner plexiform layer (IPL). The approach included an immunohistological analysis of the temporal and spatial expressions of choline acetyltransferase, of the neural-glial-related and neural-glial cell adhesion molecules (NrCAM and NgCAM, respectively) and axonin-1, and of inwardly rectifying potassium (Kir) channels in 5- to 19-day-old (E5-E19) embryos. Ultrastructural investigations evaluated whether synaptogenesis accompanies the onset of differentiation of the IPL. We found that the differentiation of the IPL started at E9. Distinct cholinergic strata appeared, NrCAM immunoreactivity showed a poorly defined stratification, and Kir3.2 was expressed in the IPL and in the inner nuclear layer. From E10 until late E14, NgCAM- and axonin-1-immunoreactive strata emerged in an alternating sequence from the outer to the inner IPL. During this period, the NrCAM pattern sharpened, and eventually five bands of weaker and stronger immunoreactivity were found. Conventional synapses formed at the beginning of E9, and stratification of the IPL also began on the same day at the same location. Synaptogenesis and stratification followed a gradient from the central to the peripheral retina. The topographic course of differentiation of the IPL generally corresponded to the course of maturation of ganglion and amacrine cells. Synaptogenesis and the expression of G-protein-gated Kir3.2 channels accompanied the onset of stratification. These events coincide with the occurrence of robust and rhythmic spontaneous neuronal activity. The subsequent differentiation of the IPL seemed to be orchestrated by several mechanisms.     

Origins of the sympathetic innervation of the cervical end of the uterus in the rat

A retrograde neuronal tracer (Fast Blue) was injected in the cervical end of the uterine horn of virgin rats. The majority of the retrogradely labeled post-ganglionic sympathetic neurons were found in the sympathetic chain (74%). The superior mesenteric ganglia, inferior mesenteric ganglia and suprarenal ganglia accounted for 22, 3 and <1%, respectively. The distribution of neurons in the sympathetic chain labeled from the uterus resembles that described for other pelvic organs.