Direct Measurements of FLASH-Induced Changes in Intracellular Oxygenation.

Autor:	El Khatib M; Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania. Electronic address: elmirna@pennmedicine.upenn.edu., Motlagh AO; Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania., Beyer JN; Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania., Troxler T; Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania., Allu SR; Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania., Sun Q; Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania., Burslem GM; Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania., Vinogradov SA; Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania. Electronic address: vinograd.upenn@gmail.com.
Jazyk:	angličtina
Zdroj:	International journal of radiation oncology, biology, physics [Int J Radiat Oncol Biol Phys] 2024 Mar 01; Vol. 118 (3), pp. 781-789. Date of Electronic Publication: 2023 Sep 18.
DOI:	10.1016/j.ijrobp.2023.09.019
Abstrakt:	Purpose: The goal of our study was to characterize the dynamics of intracellular oxygen during application of radiation at conventional (CONV) and FLASH dose rates and obtain evidence for or against the oxygen depletion hypothesis as a mechanism of the FLASH effect. Methods and Materials: The measurements were performed by the phosphorescence quenching method using probe Oxyphor PtG4, which was delivered into the cellular cytosol by electroporation. Results: Intracellular radiochemical oxygen depletion (ROD) g-value for a dose rate of 100 Gy/s in the normoxic range was found to be 0.58 ± 0.03 μM/Gy. Intracellular ROD g-values for FLASH and CONV dose rates in the normoxic range were found to be nearly equal. As in solution-based studies, intracellular ROD was found to exhibit strong dependence on oxygen concentration in the range of 0 to ∼40 μM [O 2 ]. Conclusions: Depletion of oxygen in cells in vitro by a clinical dose of proton radiation delivered as FLASH is unable to produce a transient state of hypoxia and, therefore, unable to induce radioprotection. The difference between ROD g-values for FLASH and CONV dose rates, detected previously in solutions-based experiments, disappears when measurements are conducted inside cells. Understanding this phenomenon should provide additional insight into the role of oxygen in FLASH radiation therapy and help to decipher the mechanism of the FLASH effect. (Copyright © 2023 Elsevier Inc. All rights reserved.)
Databáze:	MEDLINE
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