scholarly journals The oxidative effect of Hyperbaric Oxygen Therapy on Human retinal pigment epithelium cells

2019 ◽  
Author(s):  
Jialin Li ◽  
I-Chen Chao ◽  
Jie Luan

Abstract Background: Hyperbaric oxygen (HBO) therapy has been widely used in various diseases, which is considered safe and effective. Whereas recent studies discovered that HBO therapy could result in oxidative damage to tissues. The goal of our study was to investigate the oxidative effect of hyperbaric oxygen therapy on human retinal pigment epithelium (RPE) cells. Method: Human REP cells (ARPE-19) were cultured in vitro, and divided into normoxic group (incubated with DMEM/F12 broth)and hypoxic group (incubated with DMEM/F12 broth containing 200μmol/L CoCl2) randomly. The experimental groups were exposed to 100% pure oxygen under different pressures (0.15MPa, 0.2MPa, and 0.25MPa) for 60 and 90 minutes thrice, with 24 hours interval. Then the cell viability, 8-OHdG expression and hOGG1 expression of RPE cells were detected by MTT assay, immunocytochemistry (ICC) and western blot seperately. Result: After HBO exposure, cell proliferation decreased, 8-OHdG and hOGG1 expression increased in normoxic RPE cells compared with control group, whereas in hypoxic RPE cells, cell proliferation increased, 8-OHdG and hOGG1 expression decreased compared with hypoxic control group. Conclusion: HBO therapy could suppress the cell proliferation and cause oxidative DNA damage of RPE cells in normoxic status. Conversely, in hypoxic status, HBO therapy could promote the proliferation and ameliorate oxidative DNA damage of human retinal pigment epithelium cells. Meanwhile, HBO therapy could trigger the oxidative DNA damage repair of RPE cells in both normoxic and hypoxic statues.

1988 ◽  
Vol 91 (2) ◽  
pp. 303-312
Author(s):  
N.M. McKechnie ◽  
M. Boulton ◽  
H.L. Robey ◽  
F.J. Savage ◽  
I. Grierson

The cytoskeletal elements of normal (in situ) and cultured human retinal pigment epithelium (RPE) were studied by a variety of immunocytochemical techniques. Primary antibodies to vimentin and cytokeratins were used. Positive immunoreactivity for vimentin was obtained with in situ and cultured material. The pattern of reactivity obtained with antisera and monoclonals to cytokeratins was more complex. Cytokeratin immunoreactivity could be demonstrated in situ and in cultured cells. The pattern of cytokeratin expression was similar to that of simple or glandular epithelia. A monoclonal antibody that specifically recognizes cytokeratin 18 identified a population of cultured RPE cells that had particularly well-defined filamentous networks within their cytoplasm. Freshly isolated RPE was cytokeratin 18 negative by immunofluorescence, but upon culture cytokeratin 18 positive cells were identifiable. Cytokeratin 18 positive cells were identified in all RPE cultures (other than early primaries), regardless of passage number, age or sex of the donor. In post-confluent cultures cytokeratin 18 cells were identified growing over cytokeratin 18 negative cells, suggesting an association of cytokeratin 18 immunoreactivity with cell proliferation. Immunofluorescence studies of retinal scar tissue from two individuals revealed the presence of numerous cytokeratin 18 positive cells. These findings indicate that RPE cells can be identified by their cytokeratin immunoreactivity and that the overt expression of cytokeratin 18 may be associated with proliferation of human RPE both in vitro and in vivo.


1995 ◽  
Vol 73 (9-10) ◽  
pp. 709-722 ◽  
Author(s):  
Vitauts. I. Kalnins ◽  
Martin Sandig ◽  
Greg J. Hergott ◽  
Haruhiko Nagai

Several systems of microfilaments (MF) associated with adherens-type junctions between adjacent retinal pigment epithelial (RPE) cells and between these cells and the substratum play an important role in maintaining the integrity and organization of the RPE. They include prominent, contractile circumferential MF bundles that are associated with the zonula adherens (ZA) junctions. In chick RPE, these junctions are assembled from smaller subunits thus giving greater structural flexibility to the junctional region. Because the separation of the junctions requires trypsin and low calcium, both calcium-dependent and -independent mechanisms are involved in keeping adjacent RPE cells attached to one another. Another system of MF bundles that crosses the cell at the level of ZA junctions can be induced to form by stretching the epithelium. The MF bundles forming this system are oriented in the direction in which the RPE is stretched, thereby preventing the overextension of the cell in any one direction. The system may be useful as an indicator of the direction in which tension is experienced by RPE during development of the eye, in animal models of disease and during repair of experimentally induced wounds. Numerous single-cell wounds resulting from death of RPE cells by apoptosis at various stages of repair are normally present in developing chick and adult mammalian RPE. These wounds are repaired by the spreading of adjacent RPE cells and by the contraction of MF bundles oriented parallel to the wound edge, which develop during this time. As a result of the spreading in the absence of cell proliferation, the RPE cells increase in diameter with age. Experimentally induced wounds made by removing 5–10 RPE cells are repaired by a similar mechanism within 24 h. In repair of larger wounds, over 125 μm in width, the MF bundles oriented parallel to the wound edge characteristic of spreading cells are later replaced by stress fibers (SFs) that run perpendicularly to the wound edge and interact with the substratum at focal contacts (FCs) as RPE cells start to migrate. Cell proliferation is induced in cells along the wound edge only when the wounds are wide enough to require cell migration. In the presence of antibodies to beta-1-integrins, a component of FCs, cell spreading is not prevented but both cell migration and cell proliferation are inhibited. Thus, only the organization of the cytoskeleton characteristic of migrating RPE cells that have SFs that interact with the substratum at FCs, is associated with the induction of cell proliferation.Key words: retinal pigment epithelium, microfilaments, wound repair.


Proteomes ◽  
2018 ◽  
Vol 6 (2) ◽  
pp. 22 ◽  
Author(s):  
Sarka Beranova-Giorgianni ◽  
Francesco Giorgianni

2015 ◽  
Vol 112 (20) ◽  
pp. E2630-E2639 ◽  
Author(s):  
Andrea Milenkovic ◽  
Caroline Brandl ◽  
Vladimir M. Milenkovic ◽  
Thomas Jendryke ◽  
Lalida Sirianant ◽  
...  

In response to cell swelling, volume-regulated anion channels (VRACs) participate in a process known as regulatory volume decrease (RVD). Only recently, first insight into the molecular identity of mammalian VRACs was obtained by the discovery of the leucine-rich repeats containing 8A (LRRC8A) gene. Here, we show that bestrophin 1 (BEST1) but not LRRC8A is crucial for volume regulation in human retinal pigment epithelium (RPE) cells. Whole-cell patch-clamp recordings in RPE derived from human-induced pluripotent stem cells (hiPSC) exhibit an outwardly rectifying chloride current with characteristic functional properties of VRACs. This current is severely reduced in hiPSC-RPE cells derived from macular dystrophy patients with pathologic BEST1 mutations. Disruption of the orthologous mouse gene (Best1−/−) does not result in obvious retinal pathology but leads to a severe subfertility phenotype in agreement with minor endogenous expression of Best1 in murine RPE but highly abundant expression in mouse testis. Sperm from Best1−/− mice showed reduced motility and abnormal sperm morphology, indicating an inability in RVD. Together, our data suggest that the molecular identity of VRACs is more complex—that is, instead of a single ubiquitous channel, VRACs could be formed by cell type- or tissue-specific subunit composition. Our findings provide the basis to further examine VRAC diversity in normal and diseased cell physiology, which is key to exploring novel therapeutic approaches in VRAC-associated pathologies.


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