激光损伤对BN大鼠视网膜缝隙连接蛋白Cx43分布的影响

目的探讨细胞间隙连接蛋白(connexin 43，Cx43)在(Brown Norway，BN)大鼠视网膜中的分布特点以及氪激光损伤视网膜后Cx43分布的变化。方法应用雄性BN为研究对象，氪红激光眼底光凝(波长647nm，能量360mw，光斑直径50μm，曝光0．05s)?右眼视盘周围10个激光点。光凝后1周开始取材，应用免疫组化方法观察Cx43在BN大鼠视网膜中的分布特点。结果正常视网膜内界膜、视神经纤维层以及神经节细胞层明显表达，神经节细胞表达的主要位置是细胞浆和细胞膜，色素上皮细胞全层表达，内外颗粒层及内外丛状层无表达。激光损伤后的内界膜，视神经纤维层以及神经节细胞层Cx43表达明显减少，瘢痕区视网膜色素上皮细胞接近消失，而激光斑周边色素上皮细胞表达不受影响，激光斑部位增殖的成纤维样细胞部分表达。结论正常视网膜的Cx43主要分布在内界膜、神经纤维层、视网膜节细胞层和视网膜色素上皮层，激光损伤后内界膜、视神经纤维层以及神经节细胞层表达减弱，激光斑周围色素上皮细胞中表达无明显变化，激光损伤瘢痕中的成纤维细胞有少量表达。     

糖尿病大鼠视网膜中缝隙连接蛋白Cx43的表达

目的 观察SD大鼠视网膜细胞缝隙连接蛋白(connexin 43,Cx43)的分布及糖尿病大鼠血-视网膜屏障血管渗透性及Cx43表达变化.方法 18只SD雄性大鼠随机分成2组,糖尿病组(n=9)和正常对照组(n=9).腹腔内一次性注射链脲佐菌素制备糖尿病动物模型,伊文思蓝测量糖尿病大鼠血-视网膜屏障功能的改变,免疫组织化学技术检测Cx43的分布,结合镜下Image Pro-Plus软件半定量分析Cx43在糖尿病大鼠视网膜中表达的变化.结果 3个月时糖尿病大鼠标准化伊文思蓝含量为(25.43±3.45)ng·mg-1,与正常对照组(12.57±2.11)ng·mg-1相比较差异有统计学意义(P<0.05);Cx43在SD大鼠视网膜主要表达在神经节细胞层、神经纤维层、内丛状层、色素上皮全层,糖尿病组大鼠视网膜Cx43阳性区域的平均吸光度值(0.12±0.03)与正常对照组(0.23±0.05)相比,差异有统计学意义(P<0.05).结论 3个月时实验性糖尿病大鼠视网膜细胞Cx43表达下降,细胞间隙连接通讯功能下调,可能参与了早期糖尿病视网膜病变.     

急性高眼压大鼠视网膜RhoA的分布及表达

目的:探讨急性高眼压大鼠视网膜RhoA的分布及表达变化。方法:将56只SD大鼠随机分成正常对照组、急性高眼压后1,3,7d共4组,用免疫组化和半定量RT-PCR方法检测大鼠视网膜组织中的RhoA的分布及表达情况。结果:正常及急性高眼压后1d,RhoA主要分布于视网膜神经纤维层及神经节细胞层;3d分布于神经节细胞层及内丛状层;7d分布于神经节细胞层、内丛状层、内核层及外丛状层。半定量RT-PCR提示:在正常大鼠视网膜组织中,RhoA mRNA仅有微量表达,急性高眼压后1,3,7d,RhoA表达均显著高于正常组(P<0.05),7d组表达量最高。结论:大鼠急性高眼压损伤后,视网膜RhoA蛋白的分布及表达显著增加,其在介导抑制性信号阻断轴突再生的抑制过程中发挥着重要作用。     

丝胶对糖尿病大鼠视网膜微血管的保护作用及其作用机制

背景 糖尿病视网膜病变(DR)是一种慢性炎症性疾病,并伴有微血管病变.研究证实丝胶具有抗炎和抗氧化功能,但其是否对DR早期的微血管结构和功能有保护作用目前仍不十分清楚. 目的 观察丝胶对糖尿病大鼠视网膜中细胞间黏附分子-1(ICAM-1)、血管细胞黏附分子-1(VCAM-1)、Cx43表达的影响,探讨其对糖尿病大鼠视网膜微血管病变的防护作用.方法 将48只SPF级健康雄性SD大鼠按计算机数字随机分配法分为正常对照组、糖尿病模型组、丝胶治疗组和羟苯磺酸钙阳性对照组,每组12只.糖尿病模型组、丝胶治疗组、羟苯磺酸钙阳性对照组大鼠均采用链脲佐菌素(STZ)连续腹腔内注射3d并给予高脂饲料饮食法制备糖尿病大鼠模型,成模后分别用生理盐水、2.4 g/(kg·d)丝胶溶液和0.2 g/(kg·d)羟苯磺酸钙灌胃3个月.采用过量麻醉法处死大鼠并制备视网膜标本,采用苏木精-伊红染色法观察各组大鼠视网膜组织的形态学变化.分别采用Western blot法和逆转录PCR技术检测大鼠视网膜中ICAM-1、VCAM-1和Cx43蛋白及其mRNA的相对表达量,并对各组检测结果进行比较. 结果 正常对照组大鼠视网膜组织结构正常,糖尿病模型组视网膜可见内界膜肿胀或断裂,偶见突出于内界膜的毛细血管内皮细胞,视网膜神经节细胞(RGCs)数量减少,丝胶治疗组和羟苯磺酸钙阳性对照组大鼠视网膜内界膜轻度增厚,内外核层细胞排列稍欠规则.糖尿病模型组、丝胶治疗组和羟苯磺酸钙组阳性对照大鼠视网膜中ICAM-1和VCAM-1蛋白相对表达量较正常对照组大鼠均明显升高,而Cx43相对表达量均明显下降,差异均有统计学意义(均P＜0.05).与糖尿病模型组比较,丝胶治疗组大鼠视网膜中ICAM-1和VCAM-1蛋白相对表达量均明显降低(0.8343±0.032 l与0.918 9±0.042 4、0.7264±0.011 2与1.235 0±0.078 9),而Cx43相对表达量明显升高(0.133 1±0.015 3与0.039 2±0.002 0),差异均有统计学意义(均P＜0.05).与正常对照组比较,糖尿病组大鼠视网膜中ICAM-1mRNA和VCAM-1 mRNA相对表达量明显升高,而Cx43 mRNA表达明显下降,差异均有统计学意义(均P＜0.05);与糖尿病模型组大鼠比较,丝胶治疗组大鼠视网膜中ICAM-1 mRNA和VCAM-1 mRNA相对表达量明显下降(0.716 3±0.008 6与0.956 8±0.012 5;0.393 7±0.035 0与0.477 9±0.020 6),而Cx43 mRNA表达明显升高(0.676 8±0.064 8与0.4308±0.1113),差异均有统计学意义(均P＜0.05),各组ICAM-1 mRNA、VCAM-1mRNA和Cx43 mRNA相对表达量的变化趋势与其蛋白表达相同. 结论 丝胶能够减轻糖尿病大鼠早期视网膜的微血管病变,从而对DR的发生和发展发挥防护作用,其机制可能是下调视网膜中ICAM-1和VCAM-1的表达以及上调Cx43的表达.     

正常大鼠视网膜Mller细胞的形态学分布特征

目的:观察正常大鼠Mller细胞在视网膜不同层面的形态分布特征。方法:应用光镜和透射电镜观察正常大鼠视网膜Mller细胞的形态结构分布特征。结果:Mller细胞不均匀分布于视网膜的各个层面,在内网状层、神经节细胞层和神经纤维层分布最多。结论:Mller细胞不仅是视网膜的支架,而且在视网膜神经节细胞层与神经纤维层代谢活跃,是重要的神经胶质细胞。     

正常大鼠视网膜M-ller细胞的形态学分布特征

目的:观察正常大鼠Mller细胞在视网膜不同层面的形态分布特征。方法:应用光镜和透射电镜观察正常大鼠视网膜Mller细胞的形态结构分布特征。结果:Mller细胞不均匀分布于视网膜的各个层面,在内网状层、神经节细胞层和神经纤维层分布最多。结论:Mller细胞不仅是视网膜的支架,而且在视网膜神经节细胞层与神经纤维层代谢活跃,是重要的神经胶质细胞。     

VEGF-B及其受体Flt-1在氪激光诱导的大鼠脉络膜新生血管中的表达

目的　研究血管内皮生长因子 B(vascularendothelialgrowthfactor B ,VEGF-B)及其受体Flt-1(fms liketyrosinekinase 1,Flt-1)在氪激光诱导的棕色挪威(BrownNorway ,BN)大鼠脉络膜新生血管(choroidalneovascularization ,CNV)形成中的作用机制。方法　应用氪激光(6 4.7nm ,36 0mW ,5 0 μm ,0 .0 5s)对实验组15只BN大鼠双眼进行眼底光凝。对照组15只大鼠只散瞳不光凝。2组分别于光凝后7d、14d、2 8d、5 6d、84d行眼底荧光血管造影(fundusfluoresceinangiography ,FFA) ,然后摘除眼球制作标本进行免疫组织化学检测VEGF-B和Flt-1,原位杂交检测VEGF BmRNA。结果　VEGF BmRNA在正常BN大鼠视网膜神经节细胞层、内核层、色素上皮层、视网膜和脉络膜血管内皮细胞表达。实验眼光凝后7d ,在激光损伤区VEGF BmRNA表达于视网膜神经节细胞层、内核层、外核层缺损区、视网膜和脉络膜血管内皮细胞及CNV增殖区,14d时CNV增殖区VEGF BmRNA阳性细胞染色密度最高(P <0 .0 1) ,1月后变化差异不显著(P >0 .1)。VEGF-B蛋白质与VEGF BmRNA的表达部位及趋势相同。Flt-1在正常视网膜色素上皮细胞、外界膜及外丛状层有阳性表达,视细胞层内侧及外核层有轻度着染。实验眼光凝7d后,Flt-1在神经节细胞层、内核层、外核层缺损区及CNV增     

水通道蛋白在大鼠眼组织视网膜中的分布

目的：研究水通道蛋白1（AQP1）在正常大鼠眼组织视网膜中的分布。方法：对正常Wistar鼠眼组织切片进行免疫酶组织化学方法染色，光镜观察。正常Wistar鼠肾脏的冰冻切片为阳性对照。结果：AQP1在正常Wistar鼠视网膜的内核层有明显表达，首次发现在神经节细胞层也有明显表达，阴性对照未见。结论：AQP1在视网膜的内核层及神经节细胞层的分布，可能AQP1或AQP1和AQP4协同在高眼压和视网膜缺血状态下对维持视网膜神经细胞正常功能及细胞内外水电平衡起一定的调节作用。     

塞来昔布对糖尿病大鼠视网膜缝隙连接蛋白Cx43的作用

目的：观察COX-2(cyclooxygenase,COX-2)抑制剂(塞来昔布)对糖尿病大鼠视网膜缝隙连接蛋白Cx43(connexin43, Cx43)表达的影响。

方法：选取SD(Sprague-Dawley)大鼠45只,随机分为3组：对照组、糖尿病组、用药组,每组各15只,采用STZ腹腔注射造模的方式进行造模,快速血糖仪监测各组大鼠空腹血糖,正常对照组、糖尿病模型组、用药组分别用生理盐水、生理盐水、塞来昔布溶液进行灌胃,3mo后采用过量麻醉法处死大鼠,制备视网膜标本,采用免疫组化法观察Cx43蛋白,实时定量PCR技术检测大鼠视网膜Cx43 mRNA的相对表达量,采用SPSS13.0统计软件进行统计分析,对各组检测结果进行比较。

结果：免疫组织化学染色缝隙连接蛋白Cx43在视网膜大鼠的神经节细胞层、神经纤维层、内丛状层、色素上皮层、内皮细胞层可见表达不同程度点状、片状表达,计算机图像灰度分析发现塞来昔布对糖尿病大鼠视网膜Cx43表达有促进作用,正常对照组、糖尿病组、用药组灰度值分别是0.233±0.025、0.124±0.014、0.197±0.021,两两比较差异均有统计学意义(P<0.05); 实时定量PCR检测发现塞来昔布促进糖尿病大鼠Cx43 mRNA表达量增加,正常对照组、糖尿病组、用药组相对表达量分别是0.635±0.084、0.110±0.061、0.367±0.074,两两比较差异有统计学意义(P<0.05)。

结论：缝隙连接蛋白Cx43在糖尿病大鼠视网膜中表达减少,塞来昔布可以减缓糖尿病大鼠视网膜缝隙连接蛋白Cx43表达的减少。     

糖尿病大鼠视网膜中内质网应激蛋白的表达及意义

目的 检测内质网应激蛋白(bip)在糖尿病大鼠视网膜组织中的表达情况,探讨内质网应激在糖尿病视网膜病变(DR)中的作用和机制.方法 Wistar大鼠随机分为4组:链脲佐菌素(STZ)致糖尿病大鼠3、6、9个月模型组及正常对照组,每组10只.采用腹腔注射STZ 60 mg/kg,制备大鼠糖尿病模型;分批处死,每只大鼠左眼免疫组织化学法检测视网膜组织中bip的表达,右眼半定量RT桺CR方法 检测bip mRNA的表达.结果 bip在正常大鼠视网膜组织中少量表达,主要分布于视网膜内核层和神经节细胞层,糖尿病3个月组bip在各层的表达量升高,6个月组表达最高.结论 bip参与了DR的发病机制,在早期糖尿病大鼠视网膜组织中,细胞的应激能力随糖尿病病程延长而增强.     

Changes in connexin43 in early ocular surface development

PURPOSE: In the limbo-corneal epithelium the stem and early precursor epithelial cell pool is confined to the limbal rim. Among the features associated with this spatial segregation is the general paucity of connexin43 (Cx43) within the limbal basal cell population and its complete absence in resident stem cells. The limbo-corneal epithelial lineage derives from a Cx43-positive (Cx43+) embryonic outer ectoderm. Accordingly, as a means of identifying the process through which limbal cell phenotypes emerge, we investigated the expression of Cx43 in the ocular surface of embryonic rats. METHODS: Ocular surface expression of Cx43 or K12 was determined in cryostat sections of rat embryos and eyes using immunohistological methods. RESULTS: Changes in Cx43 expression revealed the early phenotypic divergence of three main epithelial cell phenotypes of the ocular surface. An analysis of the level and distribution pattern of Cx43 puncta lead to the identification of two distinct domains by embryonic day 10 (E10), a stage that occurs soon after formation of the lens vesicle. Additionally, at E12, ectodermal cells directly adjacent to the edges of the developing retina no longer express connexin. A comparison of anatomical and expression changes throughout embryonic development demonstrated that the two early zones represent the rudiments for the epithelia of the central cornea and conjunctiva, respectively, and that the isolated Cx43-negative (Cx43-) cells represent the precursors of the basal and, putatively, stem cells of the limbal epithelium. CONCLUSIONS: Changes in Cx43 expression revealed that the phenotypic divergence of ocular surface epithelial cells and the generation of limbo-corneal stem cell precursors takes place at a very early stage in ocular development, ahead of the establishment of any identifiable anatomical or differentiation features for these domains.     

Mapping the differential distribution of glycosaminoglycans in the adult human retina, choroid, and sclera

PURPOSE. To map the distribution of different classes of glycosaminoglycans (GAGs) in the healthy human retina, choroid, and sclera. METHODS. Frozen tissue sections were made from adult human donor eyes. The GAG chains of proteoglycans (PGs) were detected with antibodies directed against various GAG structures (either directly or after pretreatment with GAG-degrading enzymes); hyaluronan (HA) was detected using biotinylated recombinant G1-domain of human versican. The primary detection reagents were identified with FITC-labeled probes and analyzed by fluorescence microscopy. RESULTS. Heparan sulfate (HS), chondroitin sulfate (CS), dermatan sulfate (DS), and HA were present throughout the retina and choroid, but keratan sulfate (KS) was detected only in the sclera. HS labeling was particularly strong in basement membrane-containing structures, the nerve fiber layer (NFL), and retinal pigment epithelium (RPE)-for example, intense staining was seen with an antibody that binds strongly to sequences containing 3-O-sulfation in the internal limiting membrane (ILM) and in the basement membrane of blood vessels. Unsulfated CS was seen throughout the retina, particularly in the ILM and interphotoreceptor matrix (IPM) with 6-O-sulfated CS also prominent in the IPM. There was labeling for DS throughout the retina and choroid, especially in the NFL, ganglion cell layer, and blood vessels. CONCLUSIONS. The detection of GAG chains with specific probes and fluorescence microscopy provides for the first time a detailed analysis of their compartmentalization in the human retina, by both GAG chain type and sulfation pattern. This reference map provides a basis for understanding the functional regulation of GAG-binding proteins in health and disease processes.     

Molecular profiling and cellular localization of connexin isoforms in the rat ciliary epithelium

The functionally distinct epithelial layers of the ciliary body act as a syncitium to produce the aqueous humour. Ultrastructural studies have shown that the pigmented (PE) and non-pigmented (NPE) cell layers of the ciliary epithelium are connected by gap junctions. However the molecular composition of gap junctions both between and within the two cell layers has not been comprehensively studied. To address this issue the authors have performed an extensive molecular screening of connexin (Cx) expression patterns in ciliary epithelium of the rat. Initially, mRNA was extracted from rat ciliary bodies, reverse-transcribed, and subjected to two rounds of PCR using primer sets designed against each of the 14 Cx isoforms known to be expressed in the rat. This initial screening protocol amplified eight candidate Cx isoforms (Cxs 26, 31, 33, 37, 40, 43, 45 and 46). The Cx isoforms identified in this initial screen were then first assigned to the ciliary epithelium itself (Cxs 26, 31, 40 and 43) or structures outside the epithelium (Cxs 37, 40, and 45) using immunohistochemistry performed on ciliary body whole mounts. No convincing evidence for either Cx 33 or 46 labelling was found in the ciliary body. Then the four Cx isoforms localized to the epithelium were further localized to specific membrane domains within the epithelial cell layers by performing high resolution imaging of the antibody labeling patterns obtained in cryosections. This enabled Cx26 and 31 to be specifically localized to spatially different gap junctions between NPE cells. Cx31 labeled gap junctions associated with an extensive network of membrane interdigitations found between NPE cells at their basal surfaces. In contrast Cx26 labeling in NPE cells was restricted to the basolateral membranes of adjacent NPE cells. Cx40 and Cx43 were both localized to the PE-NPE interface where they formed discrete homomeric/homotypic gap junction plaques. No convincing evidence was found for antibody labeling between PE cells. Thus it appears that intercellular communication, both within the NPE layer and between the PE and NPE cell layers, is mediated by gap junction channels that have distinctive permeability properties. In particular the results raise the possibility that the permeability of PE-NPE gap junctions can be modulated by changing the Cx43 : Cx40 expression ratio. Whether such a change in Cx expression ratios occurs and what effect it has on aqueous humour production and composition remains to be determined.     

二肽基肽酶II在正常大鼠眼球各组织中的免疫表达

目的:探讨二肽基肽酶II(dipeptidyl peptidaseII,DPPII)在正常大鼠眼球各组织中的免疫表达。方法:应用抗生物素蛋白-生物素-过氧化物酶复合体法,检测DPPII在正常大鼠眼球各组织中的免疫表达。结果:发现DPPII在角膜上皮细胞、角膜基质层、角膜内皮细胞、睫状体无色素上皮细胞、虹膜色素上皮细胞、晶状体上皮细胞、晶状体纤维、视网膜神经纤维层、神经节细胞、视网膜色素上皮细胞中免疫染色均呈阳性。结论:DPPII存在于角膜上皮细胞、角膜基质层、角膜内皮细胞、睫状体无色素上皮细胞、虹膜色素上皮细胞、晶状体上皮细胞、晶状体纤维、视网膜神经纤维层、神经节细胞、视网膜色素上皮细胞。     

Benzodiazepine receptors in the eye.

Central and peripheral benzodiazepine receptors were localized in the rat, monkey, and human eye by in vitro autoradiography. Central benzodiazepine binding sites, visualized with 3H-R015-1788, were enriched in the inner plexiform layer in all three species. Binding sites also were present in the nerve fiber layer, the ganglion cell layer, and in portions of the inner nuclear layer. Peripheral benzodiazepine binding sites, visualized with 3H-PK-11195, were found in the corneal epithelium and endothelium, iris, ciliary epithelium, trabecular meshwork, and throughout the retina. Binding sites for 3H-PK-11195 also were present in the retinal pigment epithelium and choriocapillaris areas and retinal vascular structures.