Confocal Laser and Electron Microscopic Investigation of Gap Junctions in Anaplastic Astrocytomas
| Autor: | Alexander K. Logvinov, Evgeniya Yu. Kirichenko, Salah M. M. Sehweil, Denis E. Bragin, Irina K. Logvinova, Alexey M. Ermakov |
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| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | Adv Exp Med Biol Advances in Experimental Medicine and Biology ISBN: 9783031141898 |
| ISSN: | 0065-2598 |
| Popis: | Connexin 43 (Cx43) is a multifunction protein that forms gap junction channels and hemichannels and is suggested to play an essential role in oxygen-glucose deprivation, induced via neuroinflammation during astrocytoma expansion into healthy tissue. To prove this assumption we studied connexin 43 localization and ultrastructure of gap junctions in samples of malignant brain tumor (anaplastic astrocytomas grade III). For confocal laser microscopy, vibratome sections of tumors fragments were incubated in a mixture of primary antibodies to connexin 43 and glial fibrillary acidic protein (GFAP), then in a mixture of secondary antibodies conjugated with a fluorescent label. After the immunofluorescence study, sections were washed in phosphate buffer, additionally postfixed with 1% OsO4 solution, dehydrated, and embedded in epoxy resin by a plane-parallel method. Ultrathin sections obtained from these samples were contrasted with uranyl acetate and lead citrate and viewed under a Jem 1011 electron microscope. Confocal laser examination detected a positive reaction to Cx43 in the form of point fluorescence. These points were of various sizes. Most of them were localized around or at the intersection of small processes containing GFAP. Electron microscopy of the tumor samples containing the most significant number of Cx43 revealed single and closely spaced gap junctions with a typical ultrastructure on the processes and bodies of tumor cells. Sequential analysis in the fields of view revealed 62 gap junctions in the area of 100 μm(2). Numerous gap junctions in anaplastic astrocytomas revealed in our study may indicate electrotonic and metabolic transmission between glioma cells, possibly promoting its progression. |
| Databáze: | OpenAIRE |
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