Hyperhomocysteinemia (Hhcy) is an independent risk factor for Alzheimer's disease (AD). Visual dysfunction is commonly found and is positively correlated with the severity of cognitive defects in AD patients. Our previous study demonstrated that Hhcy induces memory deficits with AD-like tau and amyloid-β (Aβ) pathologies in the hippocampus, and supplementation with folate and vitamin B12 (FB) prevents the Hhcy-induced AD-like pathologies in the hippocampus. Here, we investigated whether Hhcy also induces AD-like pathologies in the retina and the effects of FB. An Hhcy rat model was produced by vena caudalis injection of homocysteine for 14 days, and the effects of FB were assessed by simultaneous supplementation with FB in drinking water. We found that Hhcy induced vessel damage with Aβ and tau pathologies in the retina, while simultaneous supplementation with FB remarkably attenuated the Hhcy-induced tau hyperphosphorylation at multiple AD-related sites and Aβ accumulation in the retina. The mechanisms involved downregulation of amyloid precursor protein (APP), presenilin-1, beta-site APP-cleaving enzyme 1, and protein phosphatase-2A. Our data suggest that the retina may serve as a window for evaluating the effects of FB on hyperhomocysteinemia-induced Alzheimer-like pathologies.
Alzheimer Disease ; etiology ; metabolism ; pathology ; therapy ; Amyloid beta-Peptides ; metabolism ; Animals ; Dietary Supplements ; Disease Models, Animal ; Folic Acid ; therapeutic use ; Homocysteine ; Hyperhomocysteinemia ; complications ; metabolism ; pathology ; therapy ; Male ; Rats, Sprague-Dawley ; Retina ; metabolism ; pathology ; Retinal Vessels ; metabolism ; pathology ; Vitamin B 12 ; therapeutic use ; tau Proteins ; metabolism

BACKGROUNDGlaucoma, an irreversible optic nerve neuropathy, always results in blindness. This study aimed to evaluate glaucoma-like features in the rat episcleral vein cauterization (EVC) model by multiple in vivo and in vitro evidences.

METHODSWistar rat was used in this study. The elevated intraocular pressure (IOP) was induced by cauterization of three episcleral veins. IOP was monitored with Tono-Pen XL tonometer. Time-dependent changes to the neuronal retinal layers were quantified by Fourier domain-optical coherence tomography. The function of retina was evaluated by electroretinogram (ERG). Survival of retinal ganglion cells (RGCs) was quantified by retrograde labeling. Histology study was performed with retinal sections stained with hematoxylin-eosin, glial fibrillary acidic protein, and neuronal nuclear antigen. Retina and aqueous humor protein were extracted and cytotoxic protein tumor necrosis factor alpha (TNF-α) and alpha-2 macroglobulin (α2m) were measured with Western blotting.

RESULTSEVC is a relatively facile intervention, with low failure rates (<5%). After surgical intervention, chronic mild IOP elevation (about 1.6-fold over normal, P < 0.05) was induced for at least 6 weeks without requiring a second intervention. High IOP causes chronic and progressive loss of RGCs (averaging about 4% per week), progressive thinning of neuronal retinal layers (3-5 μm per week), and reduction of a- and b-wave in ERG. EVC method can also induce glial cell activation and alterations of inflammation proteins, such as TNF-α and α2m.

CONCLUSIONEVC method can establish a robust, reliable, economic and highly reproducible glaucomatous animal model.

Animals ; Disease Models, Animal ; Electroretinography ; Female ; Glaucoma ; metabolism ; pathology ; Rats ; Rats, Wistar ; Retina ; metabolism ; pathology ; Retinal Neurons ; metabolism

To evaluate the effect of chlorogenic acid (CGA), a polyphenol abundant in coffee, on retinal vascular leakage in the rat model of diabetic retinopathy, Sprague-Dawley rats were divided into four groups: controls, streptozotocin-induced diabetic rats, and diabetic rats treated with 10 and 20 mg/kg chlorogenic acid intraperitoneally daily for 14 days, respectively. Blood-retinal barrier (BRB) breakdown was evaluated using FITC-dextran. Vascular endothelial growth factor (VEGF) distribution and expression level was evaluated with immunohistochemistry and Western blot analysis. Expression of tight junction proteins, occludin and claudin-5, and zonula occludens protein, ZO-1 was also evaluated with immunohistochemistry and Western blot analysis. BRB breakdown and increased vascular leakage was found in diabetic rats, with increased VEGF expression and down-regulation of occludin, claudin-5, and ZO-1. CGA treatment effectively preserved the expression of occludin, and decreased VEGF levels, leading to less BRB breakdown and less vascular leakage. CGA may have a preventive role in BRB breakdown in diabetic retinopathy by preserving tight junction protein levels and low VEGF levels.
Animals ; Blood-Retinal Barrier/*drug effects ; Chlorogenic Acid/metabolism/*pharmacology ; Claudin-5/metabolism ; Dextrans/chemistry ; Diabetes Mellitus, Experimental/complications/metabolism/*pathology ; Diabetic Retinopathy/etiology/prevention & control ; Down-Regulation ; Fluorescein-5-isothiocyanate/chemistry ; Male ; Occludin/metabolism ; Rats ; Rats, Sprague-Dawley ; Retina/*metabolism ; Tight Junction Proteins/metabolism ; Vascular Endothelial Growth Factor A/metabolism ; Zonula Occludens-1 Protein/metabolism

OBJECTIVETo investigate the expression of adiponectin and its receptors (AdipoRs) in the retina of normal mice and mice with type 1 diabetes mellitus (T1DM).

METHODSC57BL/6 mice were randomly divided into control group and streptozotocin-induced T1DM group. Two months after the modeling, the total protein and adiponectin protein expression in the retina and choroid were measured using BCA method and enzyme-linked immunosorbent assay, respectively. Quantitative RT-PCR was performed to detect the mRNA expressions of AdipoRs in the retina and choroid, and Western blotting was employed to examine the protein expressions of AdipoRs in the retina.

RESULTSAdiponectin and AdipoRs proteins were expressed in the retina and choroid in normal mice. The expressions of adiponectin and AdipoR1 were up-regulated in the retina of mice with T1DM while AdipoR2 expression exhibited no significant changes.

CONCLUSIONAdiponectin and AdipoR1 may play an important role in the evolvement of type 1 diabetic retinopathy.

Adiponectin ; metabolism ; Animals ; Diabetes Mellitus, Experimental ; metabolism ; Diabetes Mellitus, Type 1 ; metabolism ; Diabetic Retinopathy ; metabolism ; pathology ; Male ; Mice ; Mice, Inbred C57BL ; Receptors, Adiponectin ; metabolism ; Retina ; metabolism

PURPOSE: We investigated whether oxygen-induced retinopathy (OIR) results in changes in the protein expression of neuronal and inducible nitric oxide synthases (nNOS and iNOS, respectively) in rat model of OIR. In addition, we evaluated whether treatment of rats with triamcinolone acetonide (TA) prevents this response. METHODS: To promote OIR, Sprague-Dawley rats were exposed to hyperoxia from postnatal day 2 (P2) to P14. They were then returned to normoxia after P15. TA was injected into the right vitreous of P15 rats, while saline was injected into the left vitreous. At P18 the expression of nNOS and iNOS was determined using Western blotting and immunostaining techniques in retinas obtained from control rats. RESULTS: In P18 OIR rats, the abundance of nNOS and iNOS protein was significantly increased compared with controls. These increases were not observed in the retinas of rats treated with TA. The change in expression of nNOS and iNOS were specific to parvalbumin and glial fibrillary acidic protein-positive cells. Treatment with TA prevented the increased expression of nNOS and iNOS in all samples. CONCLUSIONS: Hypoxia upregulates expression of nNOS and iNOS in OIR rat retinas, which is can be prevented by treatment with TA.
Animals ; Animals, Newborn ; Anoxia/metabolism/pathology/*prevention & control ; Blotting, Western ; Disease Models, Animal ; Female ; Glucocorticoids/pharmacology ; Immunohistochemistry ; Neurons/metabolism ; Nitric Oxide Synthase Type II/*biosynthesis ; Oxygen/toxicity ; Pregnancy ; *Pregnancy, Animal ; Rats ; Rats, Sprague-Dawley ; Retina/*metabolism/pathology ; Retinal Diseases/chemically induced/pathology/*prevention & control ; Triamcinolone Acetonide/*pharmacology

OBJECTIVETo explore the effects of marrow mesenchymal stem cell (BMSC) transplantation on retinal cells apoptosis and changes to neurotrophin-3 (NT-3 and ciliary neurotrophic factor (CNTF) in rats with retinopathy of prematurity (ROP).

METHODSSeven-day-old Sprague-Dawley rats were randomly divided into normal control (CON), ROP, BMSC transplantation (BMSCs were transplanted 5 days after oxygen conditioning) and phosphate buffered saline (PBS) groups. The ROP model was prepared according to the classic hyperoxygen method. Seven days after transplantation, TUNEL/DAPI, NT-3/API and CNTF/DAPI double-labeled immunofluorescence were used to examine the effects of BMSC transplantation on both the apoptosis of retinal cells and the expression of NT-3 and CNTF protein in the retinal cells of the ROP rats.

RESULTSSeven days after BMSC transplantation, there were few TUNEL+ DAPI+ cells observed in the CON group. There were fewer TUNEL+DAPI+ cells observed in the BMSC group than in the ROP group (P<0.01), but there was no significant difference between the ROP and PBS groups (P>0.05). There were few NT-3+DAPI+ cells and CNTF+DAPI+ cells in the CON group. There were more NT-3+DAPI+ and CNTF+DAPI+ cells in the ROP group than in the CON group, but there was no significant difference between the ROP and CON groups (P>0.05). More NT-3+DAPI+ and CNTF+DAPI+ cells were observed in the BMSC group compared with the ROP group (P<0.01), and there was no significant difference in either NT-3+DAPI+ or CNTF+DAPI+ cells between the ROP and PBS groups (P>0.05).

CONCLUSIONSBMSC transplantation therapy could alleviate the apoptosis of retinal cells in ROP rats, and its mechanisms might be associated with promoting the expression of NT-3 and CNTF protein in retinal cells.

Animals ; Apoptosis ; Bone Marrow Cells ; physiology ; Cell Proliferation ; Ciliary Neurotrophic Factor ; analysis ; Female ; Humans ; In Situ Nick-End Labeling ; Infant, Newborn ; Male ; Mesenchymal Stem Cell Transplantation ; Neurotrophin 3 ; analysis ; Rats ; Rats, Sprague-Dawley ; Retina ; pathology ; Retinopathy of Prematurity ; metabolism ; therapy

OBJECTIVETo study toxic effects of 2,5-hexanedione (2,5-HD) on pathology and lipid peroxidation in mouse retina.

METHODSForty-eight mice were randomly divided into blank control group (12 mice), negative control group exposed to normal solution (12 mice) and group exposed to 2,5-HD for 2. 4 and 8 weeks, respectively (24 mice) by intraperitoneal injection (2.5% 2,5-HD) at the dose of 400 mg/kg. The pathological changes of mouse retina were examined under light microscope. The activity of superoxide dismutase (SOD) and the level of malondialdehyde (MDA) in mouse retina were detected.

RESULTSThe retinal structure in the blank and negative control groups was normal. In mice exposed to 2,5-HD for 8 weeks, the swelling of outer and inner segments and disorder arrangement of the segments without clear boundary were found. The staining of outer plexiform layers was uneven and the irregular loose structure appeared. The hyperchromatic pyknotic and necrosis nuclei were presented in ganglion cells layer. Compared with the control and blank groups, the activities of SOD gradually and significantly reduced and the concentrations of MDA increased in group exposed to 2,5-HD (P < 0.05).

CONCLUSION2,5-HD can induce the injury of retina tissues of mice, which may be associated with the lipid peroxidation.

Animals ; Hexanones ; toxicity ; Lipid Peroxidation ; drug effects ; Malondialdehyde ; metabolism ; Mice ; Mice, Inbred Strains ; Retina ; drug effects ; metabolism ; pathology ; Superoxide Dismutase ; metabolism

After two decades of ups and downs, gene therapy has recently achieved a milestone in treating patients with Leber's congenital amaurosis (LCA). LCA is a group of inherited blinding diseases with retinal degeneration and severe vision loss in early infancy. Mutations in several genes, including RPE65, cause the disease. Using adeno-associated virus as a vector, three independent teams of investigators have recently shown that RPE65 can be delivered to retinal pigment epithelial cells of LCA patients by subretinal injections resulting in clinical benefits without side effects. However, considering the whole field of gene therapy, there are still major obstacles to clinical applications for other diseases. These obstacles include innate and immune barriers to vector delivery, toxicity of vectors and the lack of sustained therapeutic gene expression. Therefore, new strategies are needed to overcome these hurdles for achieving safe and effective gene therapy. In this article, we shall review the major advancements over the past two decades and, using lung gene therapy as an example, discuss the current obstacles and possible solutions to provide a roadmap for future gene therapy research.
Adaptive Immunity ; Carrier Proteins ; genetics ; Cystic Fibrosis ; genetics ; therapy ; Cystic Fibrosis Transmembrane Conductance Regulator ; genetics ; Dependovirus ; genetics ; Eye Proteins ; genetics ; Gene Targeting ; Genetic Therapy ; methods ; Genetic Vectors ; Humans ; Immunity, Innate ; Leber Congenital Amaurosis ; genetics ; therapy ; Liposomes ; Lung ; drug effects ; metabolism ; pathology ; Mutation ; Retina ; drug effects ; metabolism ; pathology ; Retroviridae ; genetics ; cis-trans-Isomerases

OBJECTIVE: To explore the expression of cyclic guanine monophosphate (cGMP) and the ultrastructure change in retina of guinea pig with form-deprivation myopia and the underlying mechanisms. METHODS: Three-weeks-old guinea pigs were distributed in 3 groups: an untreated group (Group I), a myopia 2-weeks group (Group II) and a myopia 3-weeks group (Group III), animals underwent monocular form-deprivation by facemask for 2 and 3 weeks. The right eyes were deprived and the left eyes were self-controlled. The refraction and axial length of the eyes was measured. Retina was observed by electron microscope. The expression of cGMP was detected by radioimmunochemistry. RESULTS: Deprived eyes in guinea pig showed significant development of myopia, the refraction and axial length was increased. The pathological changes in ultrastructure of retina were aggravated with the development of myopia. The expression of cGMP was significantly up-regulated in the deprived eyes compared with self-control eyes(P<0.05). CONCLUSION Form-deprivation can up-regulate the expression of cyclic GMP, which might play an important role in the development of myopia.
Animals ; Cyclic GMP ; metabolism ; Disease Models, Animal ; Female ; Guinea Pigs ; Male ; Myopia ; etiology ; metabolism ; pathology ; Random Allocation ; Retina ; metabolism ; ultrastructure ; Sensory Deprivation ; Vision, Monocular ; physiology

PURPOSE: Retinopathy of prematurity (ROP) is one of the leading causes of blindness, with retinal detachment occurring due to oxygen toxicity in preterm infants. Recently, advances in neonatal care have led to improved survival rates for preterm infants, and ROP has increased in incidence. In the present study, we aimed to determine whether or not resveratrol exhibits protective effects in an animal model of ROP and in primary retinal cell cultures of neonatal rat via nitric oxide (NO)-modulating actions using western blotting and real-time PCR with inducible nitric oxide synthase (iNOS), endothelial NOS (eNOS) and neuronal NOS (nNOS) antibodies and mRNAs. METHODS: In an in vivo oxygen-induced retinopathy (OIR) model, cyclic hyperoxia was induced with 80% O2 for one day and 21% O2 for one day from P1 to P14 in newborn Sprague-Dawley (SD) rats. Resveratrol was injected intravitreally for seven days and rats were sacrificed at P21. In vitro OIR primary retinal cell culture was performed using P0-2 SD rats. Hyperoxia injuries were induced through 100% O2 exposure for six hours. Western blotting and real-time PCR using iNOS, eNOS, nNOS antibodies and primers were performed in the rat model of ROP and the dispersed retinal cell culture. RESULTS: In both in vivo and in vitro OIR, the expression of iNOS antibody and mRNA was increased and of eNOS and nNOS were reduced in the resveratrol-treated group. CONCLUSIONS: In conclusion, resveratrol appeared to exert retinal protective effects via modulation of NO-mediated mechanism in in vivo and in vitro OIR models.
Analysis of Variance ; Animals ; Animals, Newborn ; Blotting, Western ; Disease Models, Animal ; Electrophoresis, Polyacrylamide Gel ; Humans ; Infant, Newborn ; Nitric Oxide Synthase/*metabolism ; Oxygen/toxicity ; RNA/metabolism ; RNA, Messenger/metabolism ; Rats ; Rats, Sprague-Dawley ; Retina/drug effects/pathology ; Retinopathy of Prematurity/*metabolism/pathology/*prevention & control ; Reverse Transcriptase Polymerase Chain Reaction ; Stilbenes/*pharmacology