硫酸软骨素酶缓解视网膜变性大鼠光感受器细胞凋亡

为建立RP动物模型,经玻璃体腔注射ChABC酶,免疫荧光法观察CSPGs的表达,反转录-聚合酶链反应(RT-PCR)法检测多功能蛋白聚糖(Versican)mRNA的表达,检测光感受器凋亡情况,以探讨硫酸软骨素酶ABC(ChABC)对碘酸钠诱导的视网膜变性大鼠光感受器细胞凋亡的影响。结果表明:正常组CSPGs于脉络膜、内核层、节细胞层弱阳性表达,造模4周后CSPGs扩增到外核、外丛状层,各层荧光明显增强,而同期ChABC酶治疗组CSPGs在各层表达明显减弱;Versican mRNA表达与此一致,正常对照组、变性对照组、PBS组、治疗组Versican mRNA灰度比分别为0.18±0.02、0.92±0.03、0.98±0.06和0.30±0.01,治疗组明显低于变性组,差异极显著(P<0.01);各组光感受器凋亡率分别为(7.33±1.03)%、(40.0±2.37)%、(41.83±2.32)%、(35.2+1.94)%,治疗组显著低于变性组,差异极显著(P<0.01)。证明ChABC酶能通过降解变性大鼠视网膜异常沉积的CSPGs,抑制光感受器细胞的凋亡,从而促进损伤网膜的修复。     

鲫鱼和红腹锦鸡视网膜结构的比较组织学研究

为探讨鲫鱼(Carassius auratus)和红腹锦鸡(Chrysolophus pictus)视网膜组织结构与其生活环境的适应关系,测量了视网膜各层厚度、3个核层的胞核层数及胞核直径,并对数据进行了统计分析。结果表明:鲫鱼和红腹锦鸡视网膜均由4层细胞构成,在显微镜下分为10层。鲫鱼视网膜平均厚度为196.57μm,红腹锦鸡为225.31μm。红腹锦鸡的视网膜内核层的细胞核层数比外核层多,鲫鱼的外核层细胞核层数大于内核层。鲫鱼和红腹锦鸡这2种动物视网膜结构的差异,与其从水生到陆生的生境迁移和捕食方式的变化相适应。     

中华大蟾蜍视网膜Müller细胞形态观察

为了解两栖动物中华大蟾蜍(Bufo gargarizans)视网膜中神经胶质细胞形态结构及分布,利用生物显微技术、投射电镜技术和免疫组化技术显示了中华大蟾蜍视网膜胶质细胞形态结构。观察结果显示,中华大蟾蜍视网膜中仅分布有Müller细胞。光镜下Müller细胞在视网膜中成单层分布,细胞长轴沿着眼球半径成放射状排列,胞体位于内核层,胞体发出至少2个主干突起。电镜下视网膜Müller细胞的胞质及胞核着色较周围细胞深,细胞内有明显的纤维成分,与其他神经成分易于区别。Müller细胞近巩膜侧的主干突起延伸到视杆与视锥细胞的内节与胞核交界处,并彼此相互连接形成外界膜,近玻璃体侧的突起末端形成圆锥形的终足,锥形的底部紧邻玻璃体,且在此处彼此相互连接形成内界膜。     

棕色田鼠视网膜结构及其神经元特异性烯醇化酶分布研究

通过H-E.染色法和免疫组化方法,对棕色田鼠视网膜结构及神经元特异性烯醇化酶的分布特性进行研究.结果表明,棕色田鼠的视网膜结构呈典型的脊椎动物视网膜结构类型,由外向内分别为色素上皮、视锥视杆层、外核层、外网层、内核层、内网层、节细胞层、神经纤维层.视网膜中神经元特异性烯醇化酶阳性分布在内网层、内核层、靠近内核层的外网层区、节细胞层、神经纤维层,其中内网层阳性最强,有4个阳性亚层.视锥视杆层和外核层没有神经元特异性烯醇化酶分布,这可能与感光细胞的分泌有关.     

黄酮类化合物抑制小胶质细胞活化的构效关系研究

探讨系列黄酮类化合物抑制脂多糖(LPS)诱导的原代大鼠小胶质细胞激活的构效关系。采用MTT分析法检测细胞存活率;Griess法测定LPS激活的小胶质细胞NO释放的变化。在0.3～30μM浓度范围内,8种黄酮类化合物与LPS联合应用对小胶质细胞存活率无显著影响;黄酮、白杨素、芹菜配基、汉黄芩素、四羟黄酮5种黄酮类化合物可显著抑制LPS激活的小胶质细胞NO产生,而二羟黄酮类3种化合物(二羟黄酮、柚皮素、儿茶素)对细胞NO无显著抑制作用。黄酮类化合物母核结构中C-23,双键可能对抑制小胶质细胞激活很重要,其抑制作用的强弱取决于分子的取代类型。     

微血管周细胞与糖尿病视网膜病变中西医研究进展

大量的实验研究已经证实,微血管周细胞在糖尿病视网膜病变早期防治中扮演重要角色。为了观察和研究糖尿病视网膜病变早期微血管周细胞结构和功能变化,本文对近些年微血管周细胞的起源、形态分布、生理功能、细胞培养与鉴定、周细胞凋亡与糖尿病视网膜病变关系以及中医药防治糖尿病视网膜病变的研究进展进行综述,以期为糖尿病视网膜病变的周细胞研究及早期防治提供一种新思路。     

白藜芦醇抑制内毒素诱导小胶质细胞炎症因子表达

小胶质细胞释放的炎症介质对神经退行性疾病的发展有很重要的作用,白藜芦醇可抑制外周吞噬细胞生成和释放炎症介质。采用RT-PCR的方法在N9细胞株和原代小胶质细胞中检测了白藜芦醇对内毒素(LPS)诱导小胶质细胞肿瘤坏死因子α(TNF-α)和诱导型一氧化氮合成酶(iNOS)基因表达的影响。结果表明白藜芦醇在5~50μmol/L的浓度范围能显著的抑制TNF-α和iNOS的表达,白藜芦醇的上述抑制作用呈浓度依赖性。同时,白藜芦醇在N9细胞株中的抑制作用要稍强于原代小胶质细胞。     

烟草小孢子囊和雄配子体发育的研究

烟草小孢子囊的发育经历了孢原细胞、造孢细胞和小孢子母细胞等阶段；其雄配子体由１个生殖细胞和１个营养细胞组成，外有２层细胞壁有３个萌发孔，小孢子囊壁中的纤维层由２－３层细胞组成，此与一般被子植物不同。花药成熟时，纤维层细胞的径向壁和内切向壁上有径向条纹状加厚，并木质化。最后还讨论了小孢子囊的内部发育与花的外部形态的关系。     

点带石斑鱼脑组织和视网膜中神经型一氧化氮合成酶的分布与定位

【目的】研究点带石斑鱼脑组织和视网膜中的一氧化氮（NO）含量及神经型一氧化氮合成酶（nNOS）分布与活性,为深入揭示NO在点带石斑鱼神经系统中的作用机制打下基础。【方法】采用NADPH-d组织化学染色法、免疫组织化学法、蛋白免疫印迹（Western blotting）及Griess试剂法,对点带石斑鱼脑组织和视网膜中nNOS的分布与活性及NO含量进行分析。【结果】经NADPH-d组织化学染色后,一氧化氮合成酶（NOS）阳性物质呈蓝色。在点带石斑鱼大脑中,NOS阳性物质位于神经元和神经纤维;在小脑中,NOS分布在颗粒层的颗粒细胞、分子层的神经纤维和浦肯野细胞层的浦肯野细胞;在视网膜中,NOS分布于色素上皮层、视锥视杆层、外核层、外网层、内核层、内网层、节细胞层和视神经纤维层。经免疫组织化学染色后,nNOS阳性物质呈深棕色。在大脑中,nNOS存在于神经元和神经纤维;在小脑中,nNOS分布在颗粒层、分子层和浦肯野细胞层;在视网膜中,nNOS分布在色素上皮层、视锥视杆层、外核层、外网层、内核层、内网层、节细胞层和视神经纤维层。Western blotting检测结果显示,点带石斑鱼脑组织和视网膜中的nNOS在显色后的硝酸纤维素膜上均出现3条免疫印迹条带,对应分子量分别为80、120和130kD。NO含量在点带石斑鱼脑组织和视网膜中分别为17.601±1.743和13.624±1.249μmol/L,nNOS活性在脑组织和视网膜中分别为38.070±3.047和23.748±2.860U/mg。【结论】在点带石斑鱼脑组织和视网膜中均存在nNOS,推测nNOS在点带石斑鱼脑神经及视神经系统生理活动中发挥重要作用。脑组织中的NO含量和nNOS活性均显著高于视网膜,是由于脑组织作为重要的中枢神经,对机体生理功能起重要调节作用。     

细胞型朊蛋白在BV2小神经胶质细胞体外激活中的作用

【目的】研究细胞型朊蛋白对小神经胶质细胞不同激活方式的影响。【方法】用IFN-γ、IL-4和IL-10分别刺激BV2细胞,RT-PCR方法检测PrPC的mRNA表达量。SiRNA干扰将PrPC沉默,用上述因子刺激细胞,用RT-PCR和Western-blot检测相关参数。【结果】用IFN-γ、IL-4和IL-10分别刺激小神经胶质细胞后可导致PrPC的mRNA表达量下降;PrPC沉默后的小神经胶质细胞对IFN-γ刺激的反应应答减弱;PrPC沉默可以显著地改变由IL-4诱导的神经胶质细胞的激活表型;但是对IL-10诱导的小神经胶质细胞激活却没有影响。【结论】PrPC既能影响小神经胶质细胞从静止状态到激活状态的转换,也在小神经胶质细胞的经典激活和替代激活途径中发挥调节作用。     

Lateral interactions at inner plexiform layer of vertebrate retina: antagonistic responses to change

Lateral interactions at the inner plexiform layer of the retina of the mudpuppy were studied intracellularly after they were isolated from interactions at the outer plexiform layer with a special stimulus. The isolation was confirmed by recording no surround effect at bipolar cells under conditions that elicited a strong surround effect at ganglion cells. It appears that amacrine cell, which respond to spatiotemporal change at one retinal region, inhibit the response to change in on-off ganglion cells at adjacent sites.     

Unusual retinal cells in the dolphin eye

By comparison to the cellular constituents of the retinas of certain other diving mammals, the elements of the dolphin retina include an unusually large number of specialized cells. Both cone and rod receptors may be identified. An unusual amacrine cell may be seen which produces a process that spans the cells between the inner plexiform and outer plexiform layers. Most unusual is a layer of giant ganglion cells which appears to serve most of the central retina. The giant ganglion cells support giant dendrites and optic nerve fibers which range up to 8 micrometers in diameter.     

鳜仔鱼视网膜及口腔齿的发育对摄食的适应

采用石蜡切片及HE染色的方法对鳜受精卵及1～30 d仔鱼的视网膜结构和视觉特性进行研究,结果表明:(1)受精后54 h晶状体形成,视网膜还未分化;80 h视网膜分化为外核层、内核层、内网层和神经节细胞层4层结构;98 h形成色素上皮层、视杆视锥层和神经纤维层;124 h外网层形成,视网膜10层结构发育完全。孵化后4 d开始出现少量颌齿和咽齿;5 d和14 d分别观察到腭齿和犁齿;15d时鳃耙形成但形状较小。口腔齿的数量随着仔鱼个体的生长而增加至近于成体。(2)鳜内核层分化成一层水平细胞、数层双极细胞和无长突细胞,属光感受系统不发达的类型。(3)鳜仔鱼在消化系统尚未发育完全时已经开始形成口腔齿,为提高捕食的成功率提供了基础条件,充分表现了个体发育在进化过程中与生存环境相适应的特点。(4)鳜神经节细胞层细胞随个体的生长发育而减少,孵化后29 d,体长18.36 mm时,只有一层神经节细胞,说明此时的仔鱼已适应黑暗环境生活。鳜视觉结构的变化与其从浮游到底层的生态迁移及捕食方式的变化相适应。研究亮点:从组织学研究角度对鳜仔鱼视网膜发育进行了探讨,详细研究了视网膜各组成结构的发育特征,并结合鳜仔鱼齿的发育特征,分析了其对摄食行为的适应,首次解释了伴随着视网膜发育而形成的由浮游生活到底层生活的适应,研究结果以期为鳜在种苗生产过程中正确选择开口饵料和早期动物性饵料,以降低种苗的死亡率等提供理论依据。     

Dopamine-accumulating retinal neurons revealed by in vitro fluorescence display a unique morphology

Dopamine is the principal catecholamine neurotransmitter in the vertebrate retina. The shape of retinal neurons that accumulate dopamine has been demonstrated in an in vitro preparation of cat retina. This was achieved by the discovery that the combined uptake of dopamine and the indoleaminergic transmitter analog 5,7-dihydroxytryptamine leads to an intense, catecholamine-like fluorescence in the cell bodies and processes of presumed dopaminergic amacrine cells in the living retina. This fluorescence served as an in vitro marker for these cells, and their detailed morphology was analyzed after intracellular injection of horseradish peroxidase under direct microscopic control. The horseradish peroxidase-filled cells show an unprecedented neuronal morphology: each cell gives rise to multiple, axon-like processes that arise from, and extend for millimeters beyond, the dendritic tree. The unique structure of this type of amacrine cell suggests a function for dopamine in long-range lateral interactions in the inner plexiform layer.     

Acetylcholinesterase: method for demonstration in amacrine cells of rabbit retina

The activity of acetylcholinesterase in the inner plexiform layer of the rabbit retina was not affected detectably by prior section of the optic nerve. After the animals were treated with diisopropyl phosphorofluoridate, acetylcholinesterase reappeared in the somata of the amacrine cells and in certain cells of the ganglion cell layer before it reappeared in the inner plexiform fibers. This confirms the normal presence of acetylcholinesterase at the former site. The possible role of acetylcholine in intraretinal transmission is considered.     

Cyclic adenosine monophosphate: function in photoreceptors

Inactivation of adenylate cyclase in outer segments of retinal photoreceptor cells is proportional to the bleaching of rhodopsin. Membranes of the outer segments also contain a particulate, light-insensitive phosphodiesterase of high specific activity. In electrophysiological experiments, application of cyclic adenosine monophosphate along with a methylxanthine mimics the effects of illumination on the photoreceptor cell of the compound eye of Limulus.     

Substance P activity in the bullfrog retina: localization and identification in several vertebrate species

Immunoreactive substance P is present in the bullfrog retina, possibly in two types of stratified amacrine cells, with their somas in the inner nuclear layer and their neuronal processes entering the inner plexiform layer and ramifying in sublayers 3 or 4 (or both). Occasionally, polygonal somas positive for substance P were found in the ganglion cell layer. Approximately 75 percent of the cell bodies positive for substance P and 65 percent of the radioimmunoassayable substance P were found in the superior half of the frog retina. On the basis of high-performance liquid chromatography, the immunoreactive substance P in the neural retina of the rat, monkey, or chick is similar to synthetic substance P, whereas this is not true of the immunoreactive substance P in the bullfrog or carp retina.