X-ray microanalysis and phagocytotic activity of cultured retinal pigment epithelial cells in hypoxia
| Autor: | Hiroshi Yorifuji, Shigekuni Okisaka, Kiyoshi Akeo, Tatsushi Fujiwara |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
Clinical Biochemistry
Analytical chemistry chemistry.chemical_element Plant Science Vacuole Biology Oxygen law.invention chemistry.chemical_compound Adenosine Triphosphate Phagocytosis law Animals Viability assay Pigment Epithelium of Eye Cells Cultured Microscopy Confocal Retinal Cell Biology Glutathione Actins Cell Hypoxia Microscopy Electron chemistry Cytoplasm Biophysics Limiting oxygen concentration Cattle sense organs Electron microscope Agronomy and Crop Science Developmental Biology Electron Probe Microanalysis |
| Zdroj: | Pigment cell research. 10(5) |
| ISSN: | 0893-5785 |
| Popis: | Purpose: To investigate the influence of the functional and morphological changes induced in retinal pigment epithelial (RPE) cells by retinal ischemia, we evaluated the phagocytotic activity, the concentration of various elements, and ultrastructure in cultured RPE cells in hypoxia. Methods: The concentrations of oxygen in incubators were adjusted to 20, 10, and 1% by the addition of nitrogen for 72 hr. To observe phagocytotic activity and its relationship to actin filaments, the filaments of RPE cells incubated with fluoresbrite carboxylate YG microspheres were stained with rhodamine phalloidin. Some of the specimens were subjected to X-ray microanalysis by scanning electron microscope after being fixed, freeze-dried, and coated with carbon to investigate the cytoplasmic concentration of elements. A part of the latter specimens was also observed by transmission electron microscope after being embedded in epon and cut into ultrathin sections to see the ultra-structural changes inside cell. Results: Lowering oxygen concentrations from 20% to 1% swelled RPE cells and decreased the number of fluoresbrite carboxylate YG microspheres phagocytized by RPE cells. Phagocytosis of a large amount of latex beads (30 μl) for 24 hr in 1% oxygen caused a disruption of RPE cells. Na, S, and P were detected in RPE cells cultured in 20% oxygen. Reducing the oxygen concentration from 20 to 10 or 1% significantly decreased Na and increased S. Mitochondria were observed in RPE cells in 20 and 10% oxygen, but many vacuoles were observed in the cytoplasm in 1% oxygen. Conclusion: Hypoxia as low as 1% oxygen induced malfunction of phagocytosis and the fragility of RPE cells. We could speculate the imbalance of the electrolytes such as Na or a decrease of antioxidants such as glutathione containing S as a reason of disturbance of cell viability. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Plný text