In order to study the functional and structural alterations of the retina in SD rat model after methanol intoxication, 35 rats were divided randomly into five groups administrated with saline, 3-day high dose, 7-day high dose, 3-day low dose and 7-day low dose methanol separately. The retinal function of each group was assessed by flash electroretinogram (F-ERG) 3 and 7 days after methanol poisoning. The microstructure and ultrastructure of the retina were observed at the same time. The high-dose methanol intoxication induced irreversible retinal functional and structural damages 3 days after poisoning, which included prolonged latency and reduced amplitude of the Max-reaction of F-ERG. These injuries were aggravated 7 days after poisoning. Meanwhile, the latency and amplitude of the Cone-reaction of F-ERG were also affected 3 days after poisoning, but there were no further worsening tendency 7 days after poisoning. The retinal histological analysis showed cellular edema, heteromorphy and disarrangement, tissular loosen of the inner nuclear layer and photoreceptors layer. The mitochondrial damage began at the photoreceptors layer and developed further into the inner nuclear layer. The low-dose methanol intoxication only caused transient damage of the retina. Our results showed that the function and structure of the photoreceptor and inner nuclear layer were the primary target of methanol intoxication and that the rod cells were more sensitive to methanol intoxication than the cone cells. The mitochondrial damage developed from outer layer to inner layer of the retina.
Animals ; Edema/pathology* ; Electroretinography ; Forensic Medicine ; Male ; Methanol/poisoning* ; Mitochondria/pathology* ; Photoreceptor Cells/pathology* ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Retina/physiopathology* ; Retinal Cone Photoreceptor Cells/pathology* ; Retinal Diseases/pathology* ; Retinal Rod Photoreceptor Cells/pathology* ; Time Factors

OBJECTIVETo study the effect of Vaccinium uliginosum L., (VU) on the electroretinogram (ERG) and retinal pathological changes in rabbits after light-induced damage.

METHODSTwenty-eight Chinchilla rabbits were randomly divided into four groups: administration beforehand (A), administration after injury (B), light injury without administration (C), and blank (D) groups. After a 4-week administration of VU homogenate at 4.8 g/(kg·d) once a day in group A, ERG in groups A, B and C were recorded according to the standards set by the International Society for Clinical Electrophysiology of Vision (ISCEV). Except for group D, the groups were then exposed to strong light. Just after that, group A stopped receiving VU treatment and group B started to receive it. Then ERGs in all groups were recorded after 1 day, 1 week, and 2 weeks. Throughout the whole process groups which were not fed with VU were fed with normal saline. Finally, the tissues and structures of all the groups were observed and the thickness of the outer nuclear layers (ONL) was measured.

RESULTS(1) After 4-week feeding with VU, the latency time of ERG in group A became shorter than those in the other groups and the amplitude increased. After being exposed to strong light, the latency time lengthened and amplitude decreased in all the injury groups, but comparing at each time point, the measured values in group A were better than those in group C. With the accumulation of VU, the ERG in group B improved, and finally, all of the detected values became better than those in group C. (2) Retinae in group D were normal in histology and the layers were in order but those in group C became disarranged. The injuries in groups A and B were minor compared with those in group C. The thickness of the ONL in group C was significantly thinner than in the other groups (P=0.000), and that in groups A and B was thicker than that in group C, although thinner than in group D. That in group A was thicker than in group B.

CONCLUSIONSVU can relieve the injury to rabbit retinae exposed to normal day and night rhythm, alleviate the harm caused by light when used beforehand, and repair the light damage to the retina.

Animals ; Electroretinography ; Light ; Plant Extracts ; pharmacology ; Rabbits ; Retina ; drug effects ; pathology ; physiopathology ; radiation effects ; Retinal Cone Photoreceptor Cells ; drug effects ; pathology ; radiation effects ; Retinal Rod Photoreceptor Cells ; drug effects ; pathology ; radiation effects ; Time Factors ; Vaccinium ; chemistry

The ubiquitous Na, K-ATPase is a membrane-bound ion pump located in the plasma membrane in all animal cells and plays an essential role in a variety of cellular functions. Studies in several organisms have shown that this protein regulates different aspects of embryonic development and is responsible for the pathogenesis of several human diseases. Na, K-ATPase is an important factor for retinal development, and combinations of the isoforms of each of its subunits are expressed in different cell types and determine its functional properties. In this study, we performed RT-PCR assay to determine temporal expression and in situ hybridization to determine spatial expression of Na, K-ATPase beta2 isoform (atp1b2) in Xenopus laevis. Focusing on retinal expression to distinguish the specific expression domain, we used retinal marker genes sox4, sox11, vsx1, and . Xenopus atp1b2 was expressed from late gastrulation to the tadpole stage. Using whole mount in situ hybridization, we showed that Xenopus atp1b2 was expressed broadly in the eye, the whole surface ectoderm, and gills. In situ hybridization on sections revealed detailed and specific expression in the outer nuclear layer of the retina, which consists of two major classes of photoreceptors, rods and cones, surface ectoderm, pharyngeal epithelium, and gills. These findings indicate that atp1b2 may play an important role for the development of Xenopus retina.
Animals ; Cell Membrane ; Ectoderm ; Embryonic Development ; Epithelium ; Female ; Gastrulation ; Gills ; Humans ; In Situ Hybridization ; Ion Pumps ; Larva ; Pregnancy ; Protein Isoforms ; Retina* ; Retinal Rod Photoreceptor Cells ; Retinaldehyde ; Xenopus laevis ; Xenopus*

Animals ; Cell Survival ; radiation effects ; Light ; adverse effects ; Mice ; Mice, Knockout ; Protein Tyrosine Phosphatase, Non-Receptor Type 1 ; antagonists & inhibitors ; metabolism ; Retinal Rod Photoreceptor Cells ; cytology ; enzymology ; radiation effects

Passive transfer experiments were performed by local administrations of sera from guinea pigs hyperimmunized by bovine rod outer segments with complete Freund's adjuvant in random-bred guinea pigs. Routes of administrations were(1) single intravitreal injection of serum (25 micrl l, in 18 eyes), (2) the intravitreal injection associated with 2 subconjunctival injections (150 micrl l, in 9 eyes), (3) three subconjunctival injections of serum (150 micrl l, in 6 eyes), (4) five subconjunctival injections of serum with 2 paracenteses (in 14 eyes) and (5) four injections into the anterior chamber (50 micrl l) with 2 subconjunctival injections (in 4 eyes). Clinically animals showed cells in the anterior vitreous in 50-83% of cases. Histologically infltrations of round cells, focal or diffuse, were noted in the choroid with scattered polymorphonuclear, eosino and plasma cells. In the retina disappearance of visual cells was found, sometimes complicated by the involvement of the bipolar cells in severe cases. These findings were quite similar to the lesions produced in actively immunized animals. Choroidal lesions were most frequently found. Serum taken from the enucleated donors, and concentrated serum were more effective in the production of this transfer disese. The control experiments in which normal serum or serum immunized by adjuvant alone, revealed very low incidence of ocular lesions which were generally mild in degree. It can be concluded that humoral immunity also plays very important roles in the pathogenesis of autoimmune uveoretinitis.
Animals ; Anterior Chamber ; Choroid ; Freund's Adjuvant ; Guinea Pigs ; Humans ; Immunity, Humoral ; Incidence ; Intravitreal Injections ; Paracentesis ; Plasma Cells ; Retina ; Rod Cell Outer Segment ; Tissue Donors

After the immunization of pigmented guinea pigs with bovine rod outer segments in complete Freund's adjuvant, the regional lymph nodes were excised, teased and sedimented by centrifugation. These fresh lymphocytes were injected intravitreally (a single injection of 10 X 10 cells in 50 micro l) in 18 eyes. The involvement of the ciliary body and the choroid with polymorphonuclear leucoytes and later with round cells was noted in 16 eyes. Destructions of the visual cells of the retina were demonstrated in 8 eyes. When the fresh lymphocytes were injected subconjunctivally (50 X 10 cells in 30 micro l) four times. four of the 8 eyes showed slight infiltrations of the ciliary body and the choroid with round cells. No retinal lesion was found. Following repeated freezing and thawing of the lymphocytes. transfer experiments wereperformed with the nonviable cells and their extracts respectively. In 8 eyes injected intravitreally with nonviable cells. 2 eyes showed the infiltration of the uvea with round cells, whereas. of 6 eyes injected subconjunctivally, only one eye showed such changes. The extracts of lymphocytes were injected intravitreally in 8 eyes of which 5 eyes demon-strated moderate degree of infiltration of the uvea. Of 2 eyes injected subconjunctivally, 2 eyes. showed slight histological changes. As control experiments, lymphocytes taken from animals immunized. only with the adjuvant were treated as before and transferred to normal animals. Only one eye of 3 eyes received single intravitreal injection of fresh cells showed slight degree of infiltration of the uvea. Thus it can be concluded that the experimental autoimmune uveitis in guinea pigs could be transferred to normal animals by the transfer of non-viable lymphocytes and especially by their extracts.
Animals ; Centrifugation ; Choroid ; Ciliary Body ; Freezing ; Freund's Adjuvant ; Guinea Pigs ; Immunization ; Intravitreal Injections ; Lymph Nodes ; Lymphocytes ; Retina ; Retinaldehyde ; Rod Cell Outer Segment ; Uvea ; Uveitis*

This study was designed to determine the maximal safe drug concentration of intravitreal ciprofloxacin in phakic rabbit eyes. Twenty-two eyes of New Zealand pigmented rabbits received midvitreal ciprofloxacin of 100, 200, 400, 600 or 800 microgram in BSS Plus, or BSS Plus only. Retinal toxicity was dose-dependent as determined with electroretinography, light microscopy, and transmission electron microscopy. At a dose of greater than 400 microgram, disorganization of the outer segments was a main pathological finding in transmission electron microscopy. We evaluated retinal function by measuring the electroretinograms for a graded series of flash intensities and by fitting electroretinogram b-wave amplitudes to the Naka-Rushton equation. At a dose of greater than 600 microgram, Rmax was significantly decreased and log K was significantly increased. N-value tended to decrease. A decrease of b-wave amplitudes caused by retinal toxicity could be detected very sensitively with lower luminance stimuli. Determination of retinal toxicity with lower luminance electroretinography revealed a significant decrease of b-wave amplitudes at a dose of greater than 400 microgram. We concluded that a safe dose of intravitreal ciprofloxacin in phakic rabbit eyes was 200 microgram in phakic eyes.
Animals ; Ciprofloxacin/administration & dosage/*toxicity ; Dose-Response Relationship, Drug ; Electroretinography/drug effects ; Injections ; Lens, Crystalline ; Photic Stimulation ; Rabbits ; Retina/*drug effects/pathology/physiopathology ; Rod Cell Outer Segment/drug effects/pathology ; Vitreous Body

Ras proteins are signal-transducing GTPases that cycle between inactive GDP-bound and active GTP-bound forms. Ras is a prolific signaling molecule interacting with a spectrum of effector molecules and acting through more than one signaling pathway. The Ras-effector proteins contain a Ras-associating (RA) domain through which these associate with Ras in a GTP-dependent manner. The RA domain is highly conserved among the members of the growth factor receptor-bound (Grb) 7 family of proteins which includes Grb7, Grb10 and Grb14. Our laboratory has reported an unusual observation that RA domain of Grb14 binds to the C-terminal nucleotide binding site of cyclic nucleotide gated channel (CTRCNGA1) and inhibits the channel activity. Molecular modeling of the CTR-CNGA1 displays 50%-70% tertiary structural similarity towards Ras proteins. We named this region as Ras-like domain (RLD). The interaction between RA-Grb14 and RLD-CNGA1 is mediated through a simple protein-protein interaction temporally and spatially regulated by light and cGMP. It is interesting to note that Grb14 binds to GTPase-mutant Rab5, a Ras-related small GTPase whereas Grb10 binds only to GTP-bound form of active Rab5 but not to GTPase-defective mutant Rab5. These results suggest that Grb14 might have been evolved later in the evolution that binds to both Ras and nucleotide binding proteins such as CNGA1. Our studies also suggest that eukaryotic CNG channels could be evolved through a gene fusion between prokaryotic ion channels and cyclic nucleotide binding proteins, both of which might have undergone several sequence variations for functional adaptation during evolution.
Amino Acid Sequence ; Animals ; Cattle ; Cell Membrane ; metabolism ; radiation effects ; Conserved Sequence ; Cyclic Nucleotide-Gated Cation Channels ; genetics ; metabolism ; Evolution, Molecular ; Female ; GRB7 Adaptor Protein ; chemistry ; genetics ; metabolism ; HEK293 Cells ; Humans ; Light ; Male ; Models, Molecular ; Molecular Sequence Data ; Protein Binding ; radiation effects ; Protein Structure, Tertiary ; Protein Transport ; Rats ; Rod Cell Outer Segment ; radiation effects ; rab5 GTP-Binding Proteins ; metabolism ; ras Proteins ; metabolism