Vitreous fluorophotometry was used to measure blood retinal barrier permeability to fluorescein in 15 patients with branch retinal vein occlusion(BRVO). Mean posterior vitreous fluorescein concentration(3mm) was 20.0 +/- 11.3(ng/ml) in affected eyes, and 2.99 +/- 1.22(ng/ml) in unaffected eyes. There was a statistically significant difference between the affected eye and unaffected eye(p<0.05). Also there was a correlation between the hemorrhage area and the posterior vitreous fluorescein concentration(r2=0.819). This study revealed that the permeability of blood retinal barrier was increased in BRVO as compared to the contralateral eye, and the higher permeability values were associated with the extent of area involved.
Blood-Retinal Barrier ; Fluorescein ; Fluorophotometry ; Hemorrhage ; Humans ; Permeability ; Retina* ; Retinal Vein Occlusion* ; Retinal Vein* ; Retinaldehyde*

The panretinal photocoagulation(PRP) is known to increase the absorption of fluid through the retinal pigment epithelium by destroying blood retinal barrier. Therefore we thought that PRP could increase vitreoretinal choroidal outflow in vitreous hemorrhage. In order to investigate the effect of PRP on the absorption of vitreous hemorrhage, we performed animal experiment with 12 rabbits divided into 4 groups, and the results were as follows; 1) In phakic eyes, the vitreous hemorrhage was absorbed faster in group with PRP than in group without PRP(p<0.05). 2) The vitreous hemorrhage was absorbed faster in aphakic eyes than in phakic eyes(p<0.05). 3) In aphakic eyes, the vitreous hemorrhage was absorbed faster in group with PRP than in group without PRP, but it was not statistically significant(p>0.05).
Absorption* ; Animal Experimentation ; Blood-Retinal Barrier ; Choroid ; Rabbits ; Retinal Pigment Epithelium ; Vitreous Hemorrhage*

Advanced glycation end-product(AGE)is known as a factor causing diabetic retinopathy, but little is known about its effect on the function of outer blood-retinal barrier. To test whether AGE can increase the permeability of outer blood-retinal barrier, we injected glycated albumin into white rabbit eyes and observed the change of the fundus and of the outer blood-retinal barrier permeability. The rabbit retina in medullary ray was thickened in AGE-injected eyes. Intravenously injected microperoxidase, tracer molecule, was found in outer sensory retinal layer and outside of the retinal pigment epithelium in AGE-injected eyes. These results suggest that intraocularly injected AGE can increase the outer blood-retinal barrier permeability.
Blood-Retinal Barrier* ; Diabetic Retinopathy ; Permeability ; Retina ; Retinal Pigment Epithelium ; Retinaldehyde

Clinical ophthalmologists consider each retinal disease as a completely unique entity. However, various retinal diseases, such as uveitis, age-related macular degeneration, diabetic retinopathy, and primary open-angle glaucoma, share a number of common pathogenetic pathways. Whether a retinal disease initiates from direct injury to the blood-retinal barrier (BRB) or a defect/injury to retinal neurons or glia that impairs the BRB secondarily, the BRB is a pivotal point in determining the prognosis as self-limiting and recovering, or developing and progressing to a clinical phenotype. The present review summarizes our current knowledge on the physiology and cellular and molecular pathology of the BRB, which underlies its pivotal role in the initiation and development of common retinal diseases.
Blood-Retinal Barrier ; Diabetic Retinopathy ; Humans ; Macular Degeneration ; Phenotype ; Retinal Diseases

The blood-retinal barrier, that outward movement from the eye into the blood appears to predominate and the penetration into the eye of only a few important metabolic products is allowed, is particularly tight non-leaky junction on blood ocular barrier. In order to investigate the extent of destruction in blood retinal barrier after injection of silicone oil in the vitreous of the rabbit, author serially studied the change of fluorescein concentration in vitreous using the HPLC, ERG changes, and histopathologic changes of the retina. The results were belows, 1. The changes of fluorescein concentration in the vitreous showed increasing tendency, with time. The concentration of fluorescein were 0.008 micro/ml in 1st week, 0.069 micro/ml in 2nd week, 0.058 micro/ml in 3rd week, 0.325 micro/ml in 4th week, respectively. 2. The amplitude of photopic b wave in normal rabbit was lower than that of scotopic b wave, but there wasn't significant difference in latency between photopic and scotopic b wave. The amplitudes of b wave in silicone oil injected eyes showed lower voltage than that of normal eyes. 3. The amplitudes of b wave in silicone oil injected eyes were 210 micro V at 1st week, 150 micro V at 2nd week, 72 micro V at 3rd week, 63 micro V at 4th week in average. They showed prominent decrease in voltage from 1st week to 3rd week, but decreased slightly from 3rd week to 4th week. 4. Histopathologically, the retinal changes of the silicone oil injected eyes in 3rd week showed increased cellularity in ganglion cell layer and presented many vacuoles. In 4th week, ganglion cells were decreased but vacuoles were more increased in number.
Blood-Retinal Barrier* ; Chromatography, High Pressure Liquid ; Fluorescein ; Ganglion Cysts ; Rabbits* ; Retina ; Retinaldehyde ; Silicone Oils* ; Vacuoles

OBJECTIVEIncreased vascular endothelial growth factor (VEGF) and VEGF receptor expression is the important biological response under shear stress, ischemia and hypoxia conditions. Mechanical vibration induced cochlea shear stress and trauma obviously upregulate VEGF and VEGF receptor 2 (VEGFR2) expression in the cochlea. To evaluate the possibility of VEGF varying the transport in blood-labyrinth barrier and blood-perilymphatic barrier.

METHODSEleven guinea pigs, male and female, weighing from 300 g to 900 g were kept under general anaesthesia with xylazine (16 mg/kg) and ketamine (60 mg/kg) for both drug delivery and MRI measurement. VEGF (6 ears) and phosphate-buffered saline (PBS, 5 ears) were delivered to the inner ear via the round window membrane (soaked in gelfoam). The T1 contrast agent gadodiamide (Gd-DTPA-BMA) chelated bound paramagnetic gadolinium was used as the inner ear barrier transportation tracer. A Bruker Biospec Avance 47/40 experimental MRI system with a magnetic field strength of 4. 7 Tesla and a 40 cm bore was used for the 2-dimensional cochlea MRI evaluation. The Paravision software was used for image intensity measurement and the Adobe Photoshop 6.0 software was used for image presentation.

RESULTSVEGF induced significant Gd uptake in the scala tympani and scala vestibuli, but had little effect on the uptake of Gd in the scala media.

CONCLUSIONSVEGF significantly increased the transportation of blood-perilymphatic barrier and adapted the inner ear for compensation and repair.

Animals ; Blood-Brain Barrier ; drug effects ; Blood-Retinal Barrier ; drug effects ; Ear, Inner ; drug effects ; metabolism ; Female ; Guinea Pigs ; Magnetic Resonance Imaging ; Male ; Vascular Endothelial Growth Factor A ; pharmacology

The objective of the present study was to elucidate the effect of bisphosphonates, anti-osteoporosis agents, on glucose uptake in retinal capillary endothelial cells under normal and high glucose conditions. The change of glucose uptake by pre-treatment of bisphosphonates at the inner blood-retinal barrier (iBRB) was determined by measuring cellular uptake of [3H]3-O-methyl glucose (3-OMG) using a conditionally immortalized rat retinal capillary endothelial cell line (TR-iBRB cells) under normal and high glucose conditions. [3H]3-OMG uptake was inhibited by simultaneous treatment of unlabeled D-glucose and 3-OMG as well as glucose transport inhibitor, cytochalasin B. On the other hand, simultaneous treatment of alendronate or pamidronate had no significant inhibitory effect on [3H]3-OMG uptake by TR-iBRB cells. Under high glucose condition of TR-iBRB cells, [3H]3-OMG uptake was increased at 48 h. However, [3H]3-OMG uptake was decreased significantly by pre-treatment of alendronate or pamidronate compared with the values for normal and high glucose conditions. Moreover, geranylgeraniol (GGOH), a mevalonate pathway intermediate, increased the uptake of [3H]3-OMG reduced by bisphosphonates pre-treatment. But, pre-treatment of histamine did not show significant inhibition of [3H]3-OMG uptake. The glucose uptake may be down regulated by inhibiting the mevalonate pathway with pre-treatment of bisphosphonates in TR-iBRB cells at high glucose condition.
Alendronate ; Animals ; Blood-Retinal Barrier ; Capillaries* ; Cytochalasin B ; Diphosphonates* ; Endothelial Cells* ; Glucose* ; Hand ; Histamine ; Mevalonic Acid ; Rats* ; Retinaldehyde*

The author studied the functional derangement of blood-retinal barrier induced by destruction of the pigment epithelial cells of the retina. Sodium iodate, which was well known to exert a selectively destructive action to the retinal pigment epithelial cells, was injected to the rabbits intravenously(60mg/kg of body weight). Eyes were enucleated 2 days and 4 days after sodium iodate injection and examined by electron microscope. Some of the tissue were fixed in colloid lanthanum, to investigate the changes of the permeability of plasma membrane in accordance with cellular damages induced by sodium iodate. The permeability of the blood-retinal barrier was also studied after intravenous(200mg/kg) or intraocular(4 microgram/20ml of saline) injection of horseradish peroxidase(HRP). The results obtained were summarized as the following: Sodium iodate induced patchy areas of loss of pigment epithelial cells after 2 days, which were more widespread and severe after 4 days with regenerative activities. Loss of outer segment and mitochondrial swelling of the inner segment of visual cells were also noted after 4 days. Colloidal lanthanum penetrated into the mitochondria of pigment epithelial cells at 2 days after sodium iodate injection, which was extended to the mitochondria of inner segment of visual cells after 4 days. Intraocularly injected HRP appeared from the internal limiting membrane to Bruch's membrane after 2 days. Intravenously injected HRP appeared from the Bruch's membrane to ganglion cell layer after 2 days, which were extended to the vitreal cavity. The results suggested that the damage of the pigment epithelial cells induced by sodium iodate destroy blood-retinal barrier. HRP exudation is more extensive in direction of retina to choroid than choroid to retina.
Armoracia ; Blood-Retinal Barrier* ; Bruch Membrane ; Cell Membrane ; Choroid ; Colloids ; Epithelial Cells ; Ganglion Cysts ; Lanthanum ; Membranes ; Mitochondria ; Mitochondrial Swelling ; Permeability ; Rabbits ; Retina ; Retinal Pigment Epithelium* ; Retinaldehyde* ; Sodium

The primary purpose of the study is to investigate the destruction and recovery of the blood retinal barrier after photocoagulation and cryotherapy in the rabbits. The 110 pigmented rabbits were used in this experiment. After photocagulation and cryotherapy we injected intravenousely a dose of 25 mg/kg of fluorescein sodium, and then sampled blood and vitreous and measured the concentration of fluorescein sodium by means of High Performance Liquid Chromatography. The calculated penetration ratio which indicates the destruction of the blood retinal barrier is obtained by dividing fluorescein sodium concentration of vitreous by integral of fluorescein sodium concentration of the plasma from 3 min to 60 min. Subsequently, fundus photography and enucleation for flat preparation were performed in each experimental rabbit. The fluorescein concentration of vitreous of the normal rabbit is 3.60 +/- 4.75 X 10(-9)gm/ml and its penetration ratio is 0.20 +/- 0.23 X 10(-6) min. After measuring the correlation between the frequency of photocoagulation and penetration ratio and between the frequency of cryotherapy and penetration ratio, we found out that the correlation coefficient was 0.885 and 0.909 respectively. And this experiment showed that penetration ratio was higher in cryotherapy group than in photocoagulation group. In addition, we divided these experimental animals into 4 groups, mild and severe cryotherapy groups and lighter and heaver photocoagulation groups, and assessed the penetration ratio of these four groups at 1,3,7,14,28, and 42 days after treatment. As a result, penetration ratio was highest at 3 days after treatment and was almost back to normal by 42 days in all experimental groups except in severe cryotherapy group. Compared with photocagulation groups, cryotherapy groups showed more extensive destruction and delayed recovery of the blood retinal barrier. In fundus photography, in the photocoagulation groups white patch was developed after treatment, at 7 days white patches disappeared and were replaced by pigmented and scarred tissue; by 42 days the margin of these lesions was indistinct and the lesions were changed into relatively small scarred patches. On the other hand, in the cryotherapy groups the thick round white patch wasdeveloped after treament, at 7 days large round white patches disappeared and were replaced by pigmented and scarred tissue; by 42 days the lesions were replaced by large scarred patches with pigmentation and depigmentation. In flat preparation, in the photocoagulation groups central necrotic zone and intermediate zone with hyperpigmentation and peripheral zone with hypopigmentation was presented at 1 day. In the cryotherapy groups the diminished density, in the center and white ring at the margin was revealed at 1 day. From 7 days in photocogulation groups and from 14 days in the cryotherapy groups, retinal pigment epithelium began to show proliferation and by 42 days, retinal pigment epithelial layer of both groups except severe cryotherapy group was replaced by relatively normal retinal pigment epithelium.
Animals ; Blood-Retinal Barrier* ; Chromatography, Liquid ; Cicatrix ; Cryotherapy* ; Fluorescein ; Hand ; Hyperpigmentation ; Hypopigmentation ; Light Coagulation* ; Photography ; Pigmentation ; Plasma ; Rabbits* ; Retinal Pigment Epithelium ; Retinaldehyde

OBJECTIVE: The purpose of this study is to evaluate the effect of dexamethasone on the damaged blood-ocular barrier caused by triolein emulsion, using contrast-enhanced MR imaging. MATERIALS AND METHODS: An emulsion of 0.1-mL triolein in 20 mL of saline was infused into the carotid arteries of 32 cats, 12 cats were placed in the treatment group and 18 cats were placed in the Control group. Thirty minutes after the infusion of triolein emulsion, a set of orbital pre- and post-contrast T1-weighted MR images (T1WIs) were obtained. Infusion of 10 mg/kg dexamethasone into the ipsilateral carotid artery of each of the cats in the treatment group cats and 20 mL saline in each of the cats in the control group was given. A second set of pre- and post-contrast orbital T1WIs were obtained three hours following triolein emulsion infusion. Qualitative analysis was performed for the the anterior chamber (AC), the posterior chamber (PC), and in the vitreous humor of the ipsilateral and contralateral eyes. The signal intensity ratios of the ipsilateral eye over the contralateral eye were quantitatively evaluated in the three ocular chambers on the first and second set of T1WIs, and were then statistically compared. RESULTS: Qualitatively, the AC, the PC or the vitreous did not show immediate contrast enhancement on the first and the second set of post-contrast T1WIs. However, the AC and the PC showed delayed contrast enhancement for both groups of cats on the second pre-contrast T1WIs. No enhancement or minimally delayed enhancement was seen for the vitreous humor. Quantitatively, the signal intensity ratios in the PC of the treatment group of cats were statistically lower than the ratios of the control group of cats for the second set of T1WIs (p = 0.037). The AC and vitreous showed no statistically significant difference between the feline treatment group and control group (p > 0.05). CONCLUSION: Contrast-enhanced MR images revealed increased vascular permeability in the PC of the eye after infusion of triolein emulsion. Dexamethasone seems to decrease the breakdown of the blood-aqueous barrier in the PC.
Animals ; Blood-Aqueous Barrier/*drug effects ; Blood-Retinal Barrier/*drug effects ; Capillary Permeability/drug effects ; Cats ; Contrast Media ; Dexamethasone/*pharmacology ; Emulsions ; Glucocorticoids/*pharmacology ; Image Enhancement ; Magnetic Resonance Imaging/*methods ; Triolein/*adverse effects