title: "Modeled microgravity" affects cell response to ionizing radiation and increases genomic damage.
abstract: The aim of this work was to assess whether "modeled microgravity" affects cell response to ionizing radiation, increasing the risk associated with radiation exposure. Lymphoblastoid TK6 cells were irradiated with various doses of gamma rays and incubated for 24 h in a modeled microgravity environment obtained by the Rotating Wall Vessel bioreactor. Cell survival, induction of apoptosis and cell cycle alteration were compared in cells irradiated and then incubated in 1g or modeled microgravity conditions. Modulation of genomic damage induced by ionizing radiation was evaluated on the basis of HPRT mutant frequency and the micronucleus assay. A significant reduction in apoptotic cells was observed in cells incubated in modeled microgravity after gamma irradiation compared with cells maintained in 1g. Moreover, in irradiated cells, fewer G2-phase cells were found in modeled microgravity than in 1g, whereas more G1-phase cells were observed in modeled microgravity than in 1g. Genomic damage induced by ionizing radiation, i.e. frequency of HPRT mutants and micronucleated cells, increased more in cultures incubated in modeled microgravity than in 1g. Our results indicate that modeled microgravity incubation after irradiation affects cell response to ionizing radiation, reducing the level of radiation-induced apoptosis. As a consequence, modeled microgravity increases the frequency of damaged cells that survive after irradiation.
authors.affiliation: Dipartimento di Biologia, Università di Padova, 35121 Padova, Italy.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Canova
authors.forename: Filippo
authors.initials: F
authors.lastname: Fiorasi
authors.forename: Maddalena
authors.initials: M
authors.lastname: Mognato
authors.forename: Mauro
authors.initials: M
authors.lastname: Grifalconi
authors.forename: Elena
authors.initials: E
authors.lastname: Reddi
authors.forename: Antonella
authors.initials: A
authors.lastname: Russo
authors.forename: Lucia
authors.initials: L
authors.lastname: Celotti
mesh_terms: D017209:Apoptosis / Q000528:radiation effects; D002453:Cell Cycle / Q000528:radiation effects; D002460:Cell Line; D002470:Cell Survival / Q000528:radiation effects; D002869:Chromosome Aberrations / Q000528:radiation effects*; D002875:Chromosomes / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D015894:Genome, Human; D042822:Genomic Instability / Q000528:radiation effects*; D006801:Humans; D008214:Lymphocytes / Q000166:cytology / Q000502:physiology* / Q000528:radiation effects*; D011829:Radiation Dosage; D018474:Weightlessness Simulation / Q000379:methods*