糖尿病视网膜病变血-视网膜屏障的损伤机制

糖尿病严重影响了视网膜微循环,从而引起一系列组织结构的病理改变.这些改变最终可导致内皮细胞过度增生,血管通透性改变,异常的视网膜血管形成并发视力减退.本文阐述了高血糖对视网膜微血管系统的影响,从细胞功能和分子生物学的角度阐明高血糖所导致的细胞损伤效应.高血糖可通过影响细胞连接功能、诱导细胞凋亡以及改变细胞间的相互作用等方式对视网膜血管细胞造成损伤.这将为人们了解糖尿病视网膜病变发生发展中的分子及细胞缺陷提供新思路.     

蛋白激酶C与糖尿病视网膜病变血-视网膜屏障破坏关系的实验研究

糖尿病视网膜病变是糖尿病微血管病变中的重要表现，是糖尿病的严重并发症之一，而高血糖则是糖尿病微血管并发症发生和发展的重要危险因素。研究发现，甘油二酯（DAG）/蛋白激酶C（PKC）信号通路的激活对糖尿病微血管并发症的发生及发展有十分重要的影响。DAG-PKC通     

糖尿病血-视网膜屏障破坏的机制研究进展

血-视网膜屏障破坏所致的血管渗漏是糖尿病视网膜病变视力下降的主要原因,血管内皮细胞以及周围基质成分所构成的视网膜内屏障是受累的主要部位,血管内成分可以跨过受损的细胞间连接间隙,或通过细胞的吞饮囊泡的形态移动到组织间隙,这两种方式都在糖尿病视网膜病变中存在.内皮细胞间结构的破坏,吞饮方式的增加与高血糖异常代谢所致的氧化应激、炎症反应,以及周围其他细胞如周细胞、胶质细胞的凋亡,异常活化,以及由各种细胞所分泌的细胞因子如血管内皮生长因子(VEFG)和基质金属蛋白酶(MMP)等有密切的关系.     

五苓散对糖尿病视网膜病变大鼠血-视网膜屏障的保护作用

目的：探讨五苓散对糖尿病视网膜病变(DR)大鼠血-视网膜屏障的保护作用及其机制。

方法：SD雄性大鼠50只随机分为空白组、模型组、高剂量组、低剂量组、阳性对照组,每组10只,采用高脂高糖饮食联合腹腔注射链脲佐菌素诱导糖尿病大鼠模型。高剂量组和低剂量组大鼠采用五苓散水煎液灌胃,模型组和空白组大鼠采用等量生理盐水灌胃,阳性对照组大鼠右眼球内注射康柏西普。给药12wk后,采用酶联免疫吸附法(ELISA)检测大鼠血清C反应蛋白(CRP)和可溶性细胞间黏附分子1(sICAM-1)表达水平,HE染色观察视网膜组织结构,伊文思蓝(EB)渗漏试验观察大鼠血-视网膜屏障通透性,免疫组织化学法检测血管内皮生长因子(VEGF)在视网膜中的表达。

结果：模型组大鼠空腹血糖水平和视网膜组织EB渗透量、CRP和sICAM-1表达均较空白组明显升高,高剂量组大鼠视网膜组织EB渗透量、CRP和sICAM-1表达均低于低剂量组和阳性对照组(均P<0.05)。模型组大鼠视网膜神经节细胞层结构紊乱,视网膜水肿,VEGF表达明显升高; 与低剂量组和阳性对照组比较,高剂量组大鼠视网膜组织神经节细胞排列较清晰,水肿减轻。

结论：五苓散能有效降低糖尿病大鼠血清炎症因子水平,降低视网膜组织中VEGF的表达,减轻水肿,保护血-视网膜屏障。     

血管活性因子在糖尿病视网膜病变血-视网膜屏障损伤中的作用

糖尿病视网膜病变是糖尿病的严重并发症之一,其早期的病理基础是血-视网膜屏障的破坏,由此引起的黄斑水肿是导致视力丧失的主要原因之一.多种血管活性因子如血管内皮生长因子、色素上皮衍生因子、血小板源性生长因子、蛋白激酶C、肿瘤坏死因子α、转化生长因子β及血管紧张素Ⅱ等的异常表达是引起血-视网膜屏障损伤的直接原因.     

糖尿病大鼠血视网膜屏障损伤观察

血视网膜屏障破坏以及血管通透性增高是糖尿病视网膜微血管病变的主要病理学基础。我们以链脲佐菌素诱导的糖尿病大鼠为研究对象，观察了非增生期及临床前期糖尿病视网膜病变在发生临床可见的视网膜微血管病变前，血视网膜屏障是否已发生改变，随着病变进展其损害如何进一步加重以及此屏障功能损害与其形态结构改变的关系，现将结果报道如下。     

VEGF在糖尿病视网膜病变破坏血-视网膜屏障机制中的研究新进展

糖尿病视网膜病变(DR)是成年人视力下降甚至失明的常见原因之一,由多种发病机制共同作用,其机制虽尚未完全阐明,但血-视网膜屏障破坏是DR的关键过程。血管内皮生长因子(VEGF)作为高度内皮特异的促血管内皮生长因子,是视网膜病理性新生血管形成、破坏血-视网膜屏障的关键因子,因此全面地了解VEGF促进DR血-视网膜屏障破坏的病因病机,成为深入探索DR发病机制的关键。文章围绕DR探讨了VEGF与视网膜血管内皮细胞间的通透性、血管炎性反应、细胞凋亡反应、氧化应激、线粒体损伤以及内质网应激之间的相关机制,以期为VEGF在DR破坏血-视网膜屏障机制研究提供参考。     

糖尿病对血-视网膜屏障超微结构影响的研究进展

糖尿病视网膜病变（diabeticretinopathy,DR）是全世界最主要的致盲性眼病,也是最严重和最常见的微血管病变之一。糖尿病可造成血一视网膜屏障的损害引起血管源性水肿和神经组织损伤,造成视力下降。内层血-视网膜屏障主要是由视网膜毛细血管内皮细胞的紧密连接构成,此屏障阻碍血液的渗透及内源性物质和外源性物质在视网膜中的自由扩散,使视网膜保持恒定的环境,有效的供应营养物质。糖尿病患者的视网膜中由于细胞因子、生长因子、晚期糖基化终产物、炎症、高血糖症和周细胞丢失的增加,导致视网膜血管内皮细胞通透性增加。本文就糖尿病所引起的血-视网膜屏障超微结构改变进行综述。     

细胞因子与血-视网膜屏障损害

血 -视网膜屏障 (BRB)存在于血液和视网膜之间具有限制性通透性的结构 ,拥有精细的解剖基础和特殊的通透性特点。视网膜正常功能的保持有赖于此屏障的存在。BRB功能障碍几乎和所有的视网膜脉络膜疾病关系密切 ,尤其是血管性视网膜病变和色素上皮病变。对于BRB功能障碍发生机理的研究具有非常重要的临床意义。近年来随着细胞因子研究的不断深入 ,发现BRB功能障碍与细胞因子有很大关系 ,许多学者在此方面作了许多深入细致的工作。本文对这方面的研究进行综述。一、血 -视网膜屏障的结构基础BRB由两部分组成 ,视网膜血管内皮细胞及其连接…     

丹参通过糖尿病小鼠血-眼屏障与防治视网膜病变实验研究

目的 建立诱发小鼠糖尿病视网膜病变（d iabetic retinopathy,DRP）模型,观察疾病的发生发展病理变化,探讨中药丹参在改善DRP中的表达及防治并阐明其作用。方法 选用动物高脂肪含量的饲料喂养以单基因遗传自然发病型的糖尿病鼠进行动物活体实验,随机应用中药高中低不同剂量治疗后的糖尿病小鼠与正常小鼠视网膜组织表达进行检测并进行光学显微镜对照观察。结果 显示糖尿病小鼠视网膜内丛状层和视细胞层增厚明显,排列紊乱渗漏增强,不同剂量的丹参对小鼠糖尿病视网膜的改变表现不同。结论 糖尿病可使小鼠血-视网膜屏障受损,丹参能改善实验性DRP的影响及可能的作用机制。     

Effect of piroxicam on the blood-retina barrier in experimentally induced diabetes in rats

The effect of piroxicam on the blood-retina barrier was evaluated in rats with experimentally induced diabetes. Diabetes was induced in rats by intraperitoneal injection of streptozocin (STZ). Diabetic rats were divided into two equal groups: those treated with piroxicam, a long-acting platelet inhibitor, and an untreated control group. Vitreous fluorophotometry (VFP) was performed both before and two weeks after induction of diabetes and piroxicam intake. Streptozocin-induced diabetes caused an alteration in the blood-retinal barrier evidenced by an increase in vitreous fluorescein concentration in diabetic rats compared with normal rats. Piroxicam intake did not lead to significant change in vitreous fluorescein concentrations. However, the examination had to be terminated at two weeks because of cataract formation. The piroxicam treated group showed less incidence of lens opacity formation (59.1% compared to 81.8% in the untreated group, p = 0.0006). Piroxicam administration appears to protect the diabetic rat eye against lens opacification.This work was supported in part by U.S. Public Health Service Grants EY02377, EY07541 and EY08137 from the National Eye Institute, National Institutes of Health, Bethesda, MD and by the Juvenile Diabetes Foundation International and Pfizer, Inc.     

造血干细胞对糖尿病小鼠视网膜血管内皮细胞影响的研究

目的探讨造血干细胞(HSCs)倍增对糖尿病小鼠视网膜微血管内皮细胞的影响。方法应用小鼠干细胞生长因子(SCF)200μg·kg~(-1)·d~(-1)联合重组人粒细胞集落刺激因子(rhG-csf)50μg·kg~(-1)·d~(-1),连续5d 对糖尿病小鼠和非糖尿病小鼠分别进行自体 HSCs 动员,以生理盐水皮下注射作为对照。应用流式细胞仪以 CD34-/low 和 Scal+作为标记鉴定外周血 HSCs。应用免疫组化方法以 CD31和5-溴脱氧尿嘧啶(BrdU)标记新生的视网膜血管内皮细胞,PAS 染色标记成熟的视网膜血管内皮细胞。半定量 RT-PCR 检测血管内皮生长因子(VEGF)、可溶性血管内皮生长因子受体2(VEGFR-2)及血管生成素2(ang-2)在视网膜的表达情况。结果自体干细胞动员可以使正常小鼠和糖尿病小鼠外周血中产生 CD34-/low 和 Scal+的细胞数目倍增。在免疫组化切片上可观察到糖尿病小鼠 CD31标记的新生血管数目增多,内皮细胞更生速度加快。在 BrdU 与 CD31的免疫组化双重染色中,可观察到新生毛细血管内皮细胞两种抗原双重表达的现象。自体干细胞动员可使小鼠视网膜 VEGFR-2含量显著增高,明显下调糖尿病小鼠 VEGF 和 ang-2的表达量。结论自体 HSCs 动员可以通过外周血干细胞倍增,环境诱导分化为血管内皮细胞,双向调节 VEGF 和 ang-2等血管渗漏性相关因子,实现治疗性血管重建。     

光损伤对大鼠血-视网膜屏障功能的影响

目的：探讨强光对大鼠血－视网膜屏障功能的影响。方法：大鼠随机分为光照组及对照组,光照组大鼠经散瞳后进行10000lx强光照射（12h光照,12h避光,连续1～14d）,对照组只接受自然光线照射。分别于强光照射后第1、3、7、14 d 摘除相应的光照组和对照组大鼠双侧眼球;并用HE染色观察视网膜各层结构变化,用电镜观察视网膜超微结构变化,用伊凡思蓝（Evans blue,EB）灌注后激光共聚焦显微镜下微循环成像及分光光度法定量检测视网膜微循环通透性变化,来评估血－视网膜屏障变化。结果：大鼠在强光照射1d后就出现视网膜光感受器细胞变性、外节膜盘脱落、外核层厚度变薄等超微结构改变,并随着强光照射持续而逐渐加重,3 d后出现光感受器细胞凋亡,至14 d时外核层厚度已明显变薄、细胞数也明显减少。大鼠在强光照射1 d后视网膜血管就出现EB染料渗漏,至14 d时EB染料渗漏最明显。结论：强光照射可导致大鼠视网膜外核层光感受器细胞变性、凋亡,外核层厚度变薄、细胞数减少,血－视网膜屏障结构、功能破坏。     

Alteration of the blood-retina barriers in cases of viral retinitis

Summary This paper presents three cases of serologically documented viral retinitis, and the great value of fluorescein angiography in outlining the structural abnormalities and the site of the lesions.Of our series in the case of influenza retinitis, the fluoroangiographic findings showed dye leakage from retinal vessels in the posterior pole. The dye leakage did not appear completely in the sites of macular edema. This edema was similar to the clinical appearance of cotton-wool spots and was arranged in a star-like pattern.One of the cases of cytomegalovirus retinitis (Case 3), a previously healthy adult with dysfunction of the cellular immune system, seems to be a further example of an inflammation in the inner retina presenting cotton-wool spots at the early stage.Case 2, a previously healthy adult, fulfilled the criteria for Vogt-Koyanagi-Harada syndrome. The patient had serologically documented cytomegalovirus infection with dysfunction of the cellular immune system. The fluorescein angiographic examination showed alteration both in the inner and the outer blood-retina barriers as it is characteristic in cases of Harada syndrome. The cytomegalovirus infection might be assumed to play a role in the clinical picture as well as in the etiology of this disease.     

Adenosine enhances the relaxing influence of retinal tissue

3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins) are frequently used lipid-lowering drugs in type 2 diabetes. Recent emerging evidence suggests that statins protect cardiovascular function via lipid-independent mechanisms. However, the potential role of statins in diabetic retinopathy in type 2 diabetes is largely unclear. In the present study we have investigated the effect of lovastatin on blood-retinal barrier and inflammatory status in the retina of db/db mice and in cultured retinal cells. Male C57BL/KsJ db/db mice were randomly chosen to receive gastric gavage of lovastatin (10 mg/kg/day) or vehicle control for 6 weeks. Retinal vascular permeability, the tight junction and inflammation were determined. The results showed that db/db mice at the age of 19 weeks exhibited significantly increased retinal vascular leakage and decreased tight junction protein level in the retina. Moreover, the expression of pro-inflammatory factors, e.g. ICAM-1 and TNF-α, was drastically up-regulated in diabetic retina. Lovastatin treatment normalized all of these changes. In cultured bovine retinal capillary endothelial cells (RCECs) and human ARPE-19 cells, lovastatin attenuated the decrease of tight junction protein (occludin) and adherens junction protein (VE-cadherin) expression-induced by TNF-α, a major pro-inflammatory cytokine in diabetic retinopathy. Lovastatin also attenuated TNF-α expression in RCEC. Towards the mechanism, we showed that lovastatin ameliorated ICAM-1 expression-induced by hypoxia and TNF-α in both RCECs and ARPE-19 cells, in part through inhibition of NF-κB activation. Taken together, these findings indicate that lovastatin protects blood-retinal barrier in diabetic retinopathy, which is likely via its anti-inflammatory effects.     

Effect of Sonic hedgehog gene-modified bone marrow mesenchymal stem cells on graft-induced retinal gliosis and retinal ganglion cells survival in diabetic mice

AIM: To investigate the effects of Sonic hedgehog (Shh) gene-modified bone marrow mesenchymal stem cells (MSCs) on graft-induced retinal gliosis and retinal ganglion cells (RGCs) survival in diabetic mice. METHODS: Bone marrow-derived MSCs were genetically modified with the Shh gene to generate a stably transfected cell line of Shh-modified MSCs (MSC-Shh). Intravitreal injections of MSC-Shh and green fluorescent protein-modified MSCs (MSC-Gfp; control) were administered in diabetic mice. After 4wk, the effects of MSC-Shh on retinal gliosis were evaluated using fundus photography, and markers of gliosis were examined by immunofluorescence and Western blotting. The neurotrophic factors expression and RGCs survival in the host retina were evaluated using Western blotting and immunofluorescence. The mechanisms underlying the effects of MSC-Shh was investigated. RESULTS: A significant reduction of proliferative vitreoretinopathy (PVR) was observed after intravitreal injection of MSC-Shh compared to MSC-Gfp. Significant downregulation of glial fibrillary acidic protein (GFAP) was demonstrated in the host retina after MSC-Shh administration compared to MSC-Gfp. The extracellular signal-regulated kinase 1/2 (ERK1/2), protein kinase B (AKT) and phosphatidylin-ositol-3-kinase (PI3K) pathways were significantly downregulated after MSC-Shh administration compared to MSC-Gfp. Brain-derived neurotrophic factor (BDNF) and ciliary neurotrophic factor (CNTF) levels were significantly increased in the host retina, and RGCs loss was significantly prevented after MSC-Shh administration. CONCLUSION: MSC-Shh administration reduces graft-induced reactive gliosis following intravitreal injection in diabetic mice. The ERK1/2, AKT and PI3K pathways are involved in this process. MSC-Shh also increases the levels of neurotrophic factors in the host retina and promoted RGCs survival in diabetic mice.     

多重酪氨酸激酶受体抑制剂decorin对高糖低氧条件下血-视网膜内屏障的保护作用及机制研究

目的 研究核心蛋白多糖(decorin)对高糖低氧条件下血-视网膜内屏障的保护作用及机制.方法 培养人脐静脉内皮细胞,采用细胞计数试剂盒检测不同浓度decorin对人脐静脉内皮细胞存活率的影响;高糖低氧条件下(25 mmol·L-1右旋葡萄糖+100 μmol·L-1 CoCl2)孵育人脐静脉内皮细胞,通过ELISA检测不同浓度decorin处理后,不同时间点人脐静脉内皮细胞分泌血管内皮生长因子水平.将细胞分为正常对照组(5.5 mmol·L-1右旋葡萄糖)、高糖低氧组(25 mmol·L-1右旋葡萄糖+100 μmol·L-1 CoCl2)、甘露醇对照组(5.5 mmol·L-右旋葡萄糖+ 19.5 mmol·L-1甘露醇)及decorin处理组(25 mmol·L-1右旋葡萄糖+ 100 μmol·L-CoCl2+100 nmol · L-decorin),通过检测跨内皮细胞电阻(transendothelial electrical resistance,TER)、异硫氰酸荧光素标记的右旋糖酐(fluorescein isothiocyanate,FITC-dextran)的渗漏率来评估单层人脐静脉内皮细胞的屏障功能;Western blotting检测内皮细胞间紧密连接蛋白(claudin-5、occludin、ZO-1)及p38丝裂原活化蛋白激酶(p38 mitogen-activated protein kinase,p38 MAPK)的磷酸化水平.结果 细胞计数试剂盒检测发现,10 nmol·L-1、50 nmol·L-、100 nmol·L-1、200nmol·L-1 decorin处理人脐静脉内皮细胞24h后,各组人脐静脉内皮细胞的存活率均大于90％,差异无统计学意义(均为P＞0.05).在接种后14 d,单层人脐静脉内皮细胞的TER达到最大值且趋于稳定为(170.67±9.07)Ω.与正常对照组比较,高糖低氧处理48 h后,高糖低氧组的TER显著降低至(97.33±6.11)Ω,而decorin组的TER能够维持在(157.67±11.72)Ω,与高糖低氧组相比,差异有统计学意义(P＜0.05).高糖低氧处理48 h后,高糖低氧组FITC-dextran的渗透性明显增加,488nm处的吸光度值为正常对照组的(2.12±0.07)倍(P＜0.05).加入100 nmol·L-1的decorin处理后,FITC-dextran的渗透性明显减少,吸光度值是正常对照组的(1.16±0.03)倍,与高糖低氧组的差异有统计学意义(P＜0.05).高糖低氧处理48 h后,高糖低氧组紧密连接蛋白claudin-5表达量为0.38±0.05、occludin为0.43±0.02及ZO-1为0.25±0.02与正常对照组表达量0.72±0.05、0.90±0.01和0.75±0.02相比,差异均有统计学意义(均为P＜0.05).decorin组claudin-5、occludin及ZO-1表达量分别为0.65 ±0.08、0.87±0.03和0.60±0.01,与高糖低氧组相比,差异均有统计学意义(均为P＜0.05).高糖低氧组p-p38 MAPK/p38 MAPK的比值增加,为0.88±0.02,而decorin组p-p38 MAPK/p38 MAPK的比值(0.58±0.04)接近正常对照组水平(0.56±0.02),与高糖低氧组比较,差异有统计学意义(P＜0.05).结论 decorin能够保护高糖低氧条件下单层人脐静脉内皮细胞的屏障功能并下调p38 MAPK的表达水平,是治疗糖尿病视网膜病变的可能药物.     

自体干细胞移植术后糖尿病视网膜病变的变化分析

目的：观察自体干细胞移植术后糖尿病视网膜病变变化情况。

方法：自体干细胞移植术后糖尿病患者58例116眼经直接或间接检眼镜及眼底荧光血管造影(FFA)确定为无糖尿病视网膜病变者18眼,轻度非增殖期糖尿病视网膜病变(轻度NPDR)41眼,中度非增殖期糖尿病视网膜病变(中度NPDR)51眼,重度非增殖期糖尿病视网膜病变(重度NPDR)6眼,随访6～12mo,观察视网膜病变变化情况。

结果：患者视力、视网膜病变治疗的总有效率为84.4%、76.7%,其中重度非增殖期糖尿病视网膜病变组视力及视网膜病变治疗的有效率均显著低于轻、中度非增殖期糖尿病视网膜病变组及无视网膜病变组,差异有显著统计学意义(P<0.05)。

结论：自体干细胞移植术后稳定的血糖水平及胰岛功能的改善可能有助于稳定或延缓视网膜病变进展,其长期效果有待进一步深入研究。