眼前节内眼模拟手术诱发血眼屏障破坏的大鼠动物模型

目的 建立眼前节内眼模拟手术诱发血眼屏障破坏的大鼠动物模型。方法 清洁级健康成年雄性Sprague-Dawley大鼠150只,随机分为对照组和模型组,每组75只。按1 ml/kg的剂量腹腔注射盐酸氯胺酮 盐酸甲苯噻嗪混合液麻醉大鼠。磷酸盐缓冲液灌注袋连接三通管。三通管一端连接24G静脉留置针,手术显微镜下在3点时钟位从角巩缘前透明角膜30°斜行穿刺入前房,退出针头,留置套管;另一端连接24G静脉留置针套管,与测压计相连测量大鼠眼压。大鼠眼压波动于0～12 mm Hg（1 mm Hg=0.133 kPa）之间,波动30 次/min,重复60 次。采用氧氟沙星滴眼液滴眼。建模后第1、2、3、5、7天,采用免疫组织化学法检测大鼠白蛋白;定量检测大鼠房水、视网膜中伊凡思蓝（EB）浓度。结果 免疫组织化学染色结果显示,建模后第1、2、3、5、7天对照组白蛋白阳性染色均局限于虹膜和视网膜血管内,脉络膜弥漫性着色。建模后第1天,模型组白蛋白阳性染色主要位于虹膜和视网膜神经层血管周围;建模后第2、3天,阳性染色扩散到虹膜和视网膜全层;建模后第5、7天,阳性染色主要局限于虹膜和视网膜血管内。模型组房水中EB浓度在建模后第1、2、3、5天,均较对照组高（t=25.781,37.433,25.150,19.171;P＜0.01）;建模后第7天,与对照组接近（t=1.303,P=0.209）。模型组视网膜EB浓度在建模后第1、2、3天,均较对照组高（t=11.997,14.622,23.014;P＜0.01）;建模后第5、7天,与对照组接近（t=2.027,0.756;P=0.058,0.459）。结论 通过模拟眼前节内眼手术损伤因素,可建立内眼手术诱发的血眼屏障破坏的大鼠动物模型。     

冰片对血眼屏障通透性的影响

目的:研究冰片对家兔血眼屏障通透性的影响。方法:将42只家兔随机分为实验组和对照组,每组21只。实验组给予冰片(0.8g/kg)灌胃,对照组等体积溶媒灌胃,给药后15min耳缘静脉注射20g/L伊文思蓝(EB),分别经5,15,30,45,60,90,120min取房水及玻璃体。采用荧光分光光度法检测房水及玻璃体中的EB浓度。结果:与对照组相比,实验组房水和玻璃体中EB含量更高。结论:冰片可提高家兔血眼屏障的通透性,是一种有效促进药物透过血眼屏障的穿透促进剂。这将为某些内眼疾病的药物治疗提供新方法。     

Integrity of the blood-ocular barrier after intravitreal gas injection

The authors studied the effect of various intravitreal gases on the integrity of the blood-ocular barrier using a fluorophotometric technique. The gas (0.3 ml) was injected into the vitreous cavity of a pigment rabbit after paracentesis. Air and two long-acting gases, sulfur hexafluoride and perfluoropropane, were studied. The eyes that received only paracentesis served as controls. Fluorescein concentrations in the anterior chamber were determined by slit-lamp fluorophotometer 30 minutes following intravenous fluorescein administration. Fluorophotometry was repeated on days 1, 3, 7, and 14 after the gas injections. The eyes that received sulfur hexafluoride and perfluoropropane showed increased aqueous fluorescein concentrations in comparison with the control eyes and the air-injected eyes, although conventional slit-lamp biomicroscopic examination detected no anterior chamber inflammatory signs in these eyes. The aqueous fluorescein leakage decreased to the normal level after the intravitreal gas bubble was absorbed. These results suggest that intravitreal gas bubbles induce subclinical breakdown of the blood-aqueous barrier, which becomes re-established soon after the gas is absorbed.     

Permeability of the blood-ocular barrier in adolescent and adult diabetic patients.

The permeability of the blood-ocular barrier was examined by fluorophotometry in adolescent and adult diabetic patients before the onset of retinopathy. The adolescent group consisted of 52 eyes of 52 insulin dependent diabetic patients aged 11 to 19 years and a control group of 10 eyes of 10 normal adolescents. The adult group consisted of 74 eyes of 74 non-insulin dependent diabetics and a control group of 30 eyes of 30 normal adults. The increase in lens autofluorescence in the adolescent diabetic patients compared with the controls was striking and showed a significant positive correlation (r = 0.79, p < 0.0001) with the duration of diabetes. Anterior chamber (AQ) values, an index of the permeability of the blood-aqueous barrier (BAB), increased in the adolescent diabetic patients compared with the controls and showed a significant positive correlation with glycosylated haemoglobin levels. No significant differences from the controls were observed regarding the permeability of the blood-retinal barrier (BRB). In the adult group there was no significant difference in either the permeability of the BRB or the AQ values between the diabetic and the control groups. Our results suggest that adolescent diabetic patients differ from adults in that BAB permeability is increased before the onset of retinopathy, suggesting that this is the cause of the striking increase in lens autofluorescence.     

巩膜扣带术后血-眼屏障的早期变化研究

目的 观察巩膜扣带术对血-眼屏障的早期影响.方法 使用激光蛋白细胞检测仪对32例32眼孔源性视网膜脱离患者术前、术后的房水蛋白浓度进行定量检测,记录并比较闪辉值.术后随访1周.结果 巩膜扣带术术前、术后1 d、3 d、7 d术眼房水的平均闪辉值分别为(53.82±93.08) pc·ms-1,(15.14±21.29) pc·ms-1、(13.34±13.71) pc·ms-1、(12.89±11.28) pc·ms-1,术后第1天与术前相比差异有统计学意义(P＜0.05).其中24例单纯视网膜脱离患者术后房水平均闪辉值呈现先下降后逐渐上升的趋势,这种趋势有统计学意义(P＜0.05).8例伴有脉络膜脱离的患者术后房水平均闪辉值持续下降.结论 激光蛋白细胞检测仪可以精确的反映术后血-眼屏障的早期变化,术中冷凝血-眼屏障的影响较小,是一种安全的治疗技术.     

Dystrobrevin localization in photoreceptor axon terminals and at blood-ocular barrier sites

PURPOSE: Dystrobrevin is a newly discovered dystrophin-associated protein with multiple sites for phosphorylation on tyrosine residues. In the present study, the cellular distribution and subcellular localization of dystrobrevin were examined in the adult rat retina, cornea, lens, iris, ciliary body, and cultured Müller cells. METHODS: Immunoblot analysis, confocal laser scanning microscopy, and immunoelectron microscopy were used to examine dystrobrevin expression. RESULTS: Immunoblot analysis showed that an approximately 87-kDa band was expressed predominantly in the lens, retina, iris and ciliary body, whereas an approximately 60-kDa band was expressed in cultured Müller cells, cornea, retina, iris, and ciliary body. Confocal microscopy demonstrated dystrobrevin in the inner limiting membrane, outer plexiform layer, and retinal pigment epithelium and around blood vessels in the retina. At the ultrastructural level, dystrobrevin was localized under cell membranes of rod spherules and cone pedicles of photoreceptor cell terminals but often was found in the cytoplasm of endothelial cells and Müller cells. Furthermore, dystrobrevin was colocalized with beta-dystroglycan in corneal endothelium; lens, iris, and ciliary epithelia; and cultured Müller cells. CONCLUSIONS: The present study demonstrates that dystrobrevin is expressed in neurons, glia, and endothelial cells in the rat retina. In addition, dystrobrevin is localized at the blood-ocular barrier sites in extraocular tissue. These data suggest that dystrobrevin plays an important role in visual function.     

The effect of partial vitrectomy on blood-ocular barrier function in the rabbit

PURPOSE: To compare ocular vascular permeability in the rabbit after vitrectomy as assessed by contrast-enhanced magnetic imaging (CE-MRI) and measurements of aqueous and vitreous humor protein concentration. METHODS: Partial vitrectomies were performed, irrigating with BSS or BSS PLUS. Post-operative vascular leakage was determined by CE-MRI following intravenous administration of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA). Aqueous and vitreous protein concentrations were quantified by standard biochemical assay. ERG evaluations were performed on postoperative days 1, 3, and 7. RESULTS: Using BSS as irrigant, breakdown of the inner blood-retinal barrier (BRB) occurred in 4/7 eyes on post-operative day 1. The rate of Gd-DTPA leakage was significantly greater on postoperative day 1 than that in unoperated, control eyes, but declined approximately 50% by day 3. At both time points, outer BRB breakdown was restricted to the sclerotomy wounds. No BRB leakage was detectable in control eyes. Blood-aqueous barrier (BAB) leakage was bilateral on day 1. Significantly greater Gd-DTPA leakage occurred in the operated eye than in the nonsurgical contralateral eye. On day 3, approximately 40% bilateral reduction in leakage indicated resolution of BAB leakage. Notably, Gd-DTPA leakage of the BAB and BRB was significantly reduced in the BSS PLUS treated group. In contrast to MRI assessments, protein concentrations of the aqueous and vitreous in the surgical eye showed no detectable differences between BSS and BSS PLUS. Concurrent with the transient loss of ocular barrier function, ERG responses also declined. However, by day 7 greater than 90% recovery was noted in BSS PLUS treated animals but not in the BSS treatment group. CONCLUSIONS: CE-MRI is capable of detecting subtle changes in vascular permeability following ocular surgery. Advantages of using BSS PLUS compared to BSS as the irrigating solution can be detected using this technique. BSS PLUS's protection of barrier function is consistent with a rapid recovery in retinal function not observed in BSS treated eyes.     

Permeability of the blood-ocular barrier to mannitol and PAH during experimental diabetes

The simultaneous uptake of mannitol, a passive permeability marker, and the organic acid, p-aminohippuric acid, was measured in the anterior and posterior vitreous and retina. Uptake was determined in control, probenecid treated and streptozocin diabetic rats. The unidirectional influx, calculated as a 10 minute PS product for these compounds, was not increased by 2, 4, or 12 weeks of diabetes. A clearance value, calculated using an experimental time of 60 minutes was also examined in order to gauge efflux of these compounds from the eye. The 60 minute clearance value for mannitol in the retina increased approximately 75% in 2, 4, and 12 week diabetic rats. This was an unexpected result due to the lack of increase in the unidirectional flux of mannitol during these same periods of diabetes, and may represent a change in the passive efflux out of the retina. The 60 minute clearance value for mannitol was not significantly changed in either the anterior or posterior vitreous. Experimental diabetes increased the 60 minute clearance value for PAH for the retina by 40% to 70%. In contrast, diabetes did not increase influx of PAH into the anterior or posterior vitreous. Because the unidirectional influx of PAH into the retina was not increased during diabetes, a decrease in the active transport for organic acids out of the eye is a likely explanation for the increase in the 60 minute clearance value for PAH during diabetes.     

曲安奈德术中眼内注射对血眼屏障的保护作用

目的评价术中玻璃体腔内注射曲安奈德(triamcinolone acetonide)对复杂的玻璃体视网膜手术术后血眼屏障的保护作用。方法11例(13眼)复杂的玻璃体视网膜手术,手术结束后,将曲安奈德混悬液注入玻璃体腔内,在硅油填充眼,曲安奈德的注入量为0.05mL(2mg),非硅油填充眼为0.1mL(4mg)。手术后随访2~4月,观察曲安奈德颗粒的消失时间、抗炎效果和并发症。结果曲安奈德颗粒从眼内消失的时间,硅油填充眼为2~3月,非硅油填充眼为1~1.5月。术后均未出现明显的早期眼部炎症反应。眼压升高2眼,1眼由硅油引起,另1眼发生在手术后4月,由葡萄膜炎引起。无与曲安奈德相关的并发症发生。结论对复杂的玻璃体视网膜手术,术中玻璃体腔内注射曲安奈德可有效地防止血眼屏障破坏,减轻手术后眼部炎症反应。     

Fluorophotometric evaluation of the blood-ocular barrier function following cataract surgery and intraocular lens implantation

Ocular fluorophotometry is a sensitive method for quantitative, in vivo evaluation of the blood-ocular barrier function. This paper reviews studies that have used this technique to evaluate the effects of devices or techniques used in cataract and implant surgery.     

Changes in ocular structure and in blood-ocular barrier permeability of experimental myopia induced in monkeys

We induced myopia by eyelid suturing in one eye each of six 9-month-old cynomolgus monkeys to elucidate the condition by studying changes in the ocular structure and the blood-ocular barrier (BOB) permeability. Optical elements were measured by A-mode ultrasonography; vitreous fluorophotometry was carried out to document BOB permeability before eyelid suturing and 3, 10, 16, and 28 months after suturing. The axial length of the sutured eyes increased significantly compared with that of the non-sutured contralateral eyes at 10 months after suturing and continued to lengthen with time. The dioptric power (D) of the sutured eyes changed in the same way. (mean, -3.08D 28 months after suturing). The permeability of the blood-retinal barrier of the sutured eyes significantly increased from 10 months after suturing compared with that of the fellow eyes, and continued to increase over the period of observation. The permeability index of the blood-aqueous barrier also increased significantly from only 16 months after suturing further increasing as the period of observation lengthened. We hypothesize that in the transition from emmetropia to myopia, the permeability of the BOB rises, and continue to rise as myopia develops. Thus, the breakdown of the BOB, i.e., the breakdown of the ocular homeostasis, is considered to be closely related to the occurrence and the development of myopia.     

Early breakdown of the blood-retinal barrier in diabetes.

The blood-retinal barrier plays an important part in the processes of retinal pathophysiology. A new clinical method for the study of the blood-retinal barrier by vitreous fluorophotometry appears to satisfy the necessary requirements in that it is quantitative and shows good reproducibility and high sensitivity. The application of this method to a series of diabetic patients with apparently "normal" fundi revealed the presence of a significant breakdown of the blood-retinal barrier in the early stages of retinal involvement in diabetes. The extent of the breakdown can be measured allowing for comparative and evolutionary evaluations. The disturbance of the blood-retinal barrier, as evidence by vitreous fluorophotometry, appears before microaneurysms or capillary closure can be demonstrated by fluorescein angiography.     

VEGF-initiated blood-retinal barrier breakdown in early diabetes

PURPOSE: The objectives of this study were to (1) determine whether endogenous vascular endothelial growth factor (VEGF) triggers diabetic blood-retinal barrier breakdown, and (2) identify the site as well as phenotype of the hyperpermeable diabetic retinal vessels. METHODS: Retinal VEGF mRNA levels were quantified in 1-week diabetic rats using the RNase protection assay. VEGF bioactivity was blocked via the systemic administration of a highly specific VEGF-neutralizing soluble Flt/F(c) construct (VEGF TrapA(40)). An inactive IL6 receptor/F(c) construct (IL6R Trap) was used as an isotype control. Blood-retinal barrier breakdown was quantified using the Evans blue technique and was spatially localized with fluorescent microspheres. RESULTS: Retinal VEGF mRNA levels in 1-week diabetic animals were 3.2-fold higher than in nondiabetic controls (P < 0.0001). Similarly, retinal vascular permeability in 8-day diabetic animals was 1.8-fold higher than in normal nondiabetic controls (P < 0.05). Diabetes-induced blood-retinal barrier breakdown was dose-dependently inhibited with VEGF TrapA(40), with 25 mg/kg producing complete inhibition of the diabetes-induced increases (P < 0.05). Blood-retinal barrier breakdown in diabetic animals treated with solvent alone or IL6R Trap did not differ significantly from untreated diabetic animals (P > 0.05). Spatially, early blood-retinal barrier breakdown was localized to the retinal venules and capillaries of the superficial retinal vasculature. CONCLUSIONS: Early blood-retinal barrier breakdown in experimental diabetes is VEGF dependent and is restricted, in part, to the venules and capillaries of the superficial inner retinal vasculature. VEGF inhibition should prove a useful therapeutic approach in the treatment of early diabetic blood-retinal barrier breakdown.     

The specific features of penetration of the antioxidant histochrome across the blood-ocular barrier: an experimental study

Analysis of intraocular fluid and the vitreous body in 7 rabbits (14 eyes) by high performance liquid chromatography reveals histochrom metabolic products and, possibly, histrochrom itself during intravenous and subconjunctival injections and retrobulbar administration of histochrom through the irrigation system on models of experimental rabbit hyphema and hemophthalmia, which suggests that histochrom is able to penetrate across the blood-ocular barrier.     

对比增强磁共振在虹膜周边切除术后兔眼前后房屏障研究中的作用

背景 眼前后房间是否构成血—眼屏障的一部分一直存有争议,传统的检测方法由于不能测量后房房水的情况而无法提供更好的证据.目的 使用对比增强磁共振成像(MRI)研究兔眼虹膜周边切除术后造影剂在前后房的分布,证实眼前后房之间的屏障作用.方法 8只清洁级新西兰白兔单眼接受虹膜周边切除术,对侧眼为对照眼.MRI的造影剂钆喷酸葡胺(Gd-DTPA)作为示踪剂,在活体兔耳缘静脉注射0.5 mol/L造影剂0.2 ml/kg,MRI连续扫描,观察造影剂的渗透性及眼内分布,通过感兴趣区时间相关的信号增强率分析影像.结果 兔耳缘静脉注射0.2 ml/kg Gd-DTPA后,双眼睫状体信号在10 min内快速增强,且手术眼的荧光强度强于对照眼.Gd-DTPA注射后30～40 min睫状体信号最强,此后逐渐下降,前房信号逐渐增强,手术眼后房信号增强,而对照眼后房呈低信号,Gd-DTPA注射后感兴趣区分别为睫状体、前房和后房,手术眼后房信号增强与前房同步,对照眼后房未发现信号增强.结论 血浆蛋白进入前房途径与房水分泌途径是分别独立的通道,眼前后房之间存在着屏障,是血—眼屏障的组成部分.