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Induction of DNA-strand breaks after X-irradiation in murine bone cells of various differentiation capacities

Lau, Patrick and Hellweg, Christine E. and Kirchner, Simone and Baumstark-Khan, Christa (2005) Induction of DNA-strand breaks after X-irradiation in murine bone cells of various differentiation capacities. Advances in Space Research, 36, pp. 1689-1695. Elsevier.

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Abstract

During longterm space missions, astronauts suffer from the loss of minerals especially from weightbearing bones due to prolonged sojourn under microgravity. In addition to weightlessness, exposure to cosmic ionization radiation is another space related factor endangering health and productivity of astronauts. In order to elucidate changes in bone cell metabolism induced by ionizing radiation, ground-based bone cell models have been developed. The differentiation level of the bone cells may influence their radiation sensitivity. Therefore, our cell model comprises a collection of immortalized murine pre-osteoblast, osteoblast and osteocyte cell lines representing discrete stages of differentiation: the subclones 4 and 24 of the osteoblast cell line MC3T3-E1, the osteoblast cell line OCT-1 and the osteocyte cell line MLO-Y4 display varying potential to produce mineralized bone matrix upon incubation with ascorbic acid and b-glycerophosphate (osteogenic medium). The MLO-Y4 cells showed the highest and subclone 24 the lowest proliferation rate. The most intense von Kossa reaction after culture in osteogenic medium was observed in subclone 4, indicating mineralized bone matrix. The bone cell markers alkaline phosphatase and osteocalcin were determined to further characterize the differentiation stage. All cell lines expressed osteocalcin, as determined by reverse transcriptase polymerase chain reaction. The activity of alkaline phosphatase was highest in the cell line OCT-1 and very low in MLO-Y4 and S4. The peculiarity of the markers suggests a characterization of OCT-1 and S24 as preosteoblast, S4 as (mature) osteoblast, and MLO-Y4 as osteocyte. Survival after exposure to X-rays was determined using the colony forming ability test. The resulting dose–effect relationships revealed normal radiation sensitivity (compared to human fibroblasts). Cell clone specific variations (subclones 4 and 24) in the radiation sensitivity may be due to the differentiation level. The survival curve of MLO-Y4 shows a broad shoulder, suggesting a high repair capacity or a high DNA damage or misrepair tolerance. The quantitative acquisition of DNA-strand breaks was performed by fluorescent analysis of DNA unwinding and revealed a high level of DNA damage immediately after X-irradiation, which increases dose dependently. In conclusion, the cell line with the highest differentiation level (MLO-Y4) displays lower radiation sensitivity, regarding the shoulder width of the dose–effect curve, compared to the less differentiated osteoblast cell lines.

Item URL in elib:https://elib.dlr.de/47505/
Document Type:Article
Title:Induction of DNA-strand breaks after X-irradiation in murine bone cells of various differentiation capacities
Authors:
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Lau, PatrickUNSPECIFIEDUNSPECIFIED
Hellweg, Christine E.UNSPECIFIEDUNSPECIFIED
Kirchner, SimoneUNSPECIFIEDUNSPECIFIED
Baumstark-Khan, ChristaUNSPECIFIEDUNSPECIFIED
Date:2005
Journal or Publication Title:Advances in Space Research
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:Yes
Volume:36
Page Range:pp. 1689-1695
Editors:
EditorsEmailEditor's ORCID iD
COSPAR, UNSPECIFIEDUNSPECIFIED
Publisher:Elsevier
Status:Published
Keywords:Space, Ionizing radiation, Murine osteoblasts, Differentiation level, Survival, Strand breaks
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Space (old)
HGF - Program Themes:W FR - Forschung unter Weltraumbedingungen (old)
DLR - Research area:Space
DLR - Program:W FR - Forschung unter Weltraumbedingungen
DLR - Research theme (Project):W - Vorhaben Strahlenbiologie (old)
Location: Köln-Porz
Institutes and Institutions:Institute of Aerospace Medicine > Radiation Biology
Deposited By: Kopp, Kerstin
Deposited On:05 Mar 2007
Last Modified:27 Apr 2009 13:34

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