Lack of a differential radiation response for proliferative and non-proliferative rat thyroid cells (FRTL-5) in vitro
FRTL-5 rat thyroid epithelial cells maintain normal thyroid function and morphology in vitro, exhibit an absolute requirement for thyroid stimulating hormone (TSH) for proliferation and display radiation dose response characteristics indistinguishable from those of rat thyroid epithelial cells in vivo. In TSH-free medium cells remain in a non-proliferative, yet viable, state for prolonged periods of time and respond to TSH re-stimulation by a return to exponential growth. Flow cytometric analysis using two-step acridine orange (AO) staining revealed an accumulation of cells in the G1 phase of the cell cycle accompanied by a pronounced reduction in red fluorescence (indicative of RNA content) in FRTL-5 cells cultured in the absence of TSH. The response of proliferative and non-proliferative FRTL-5 cells to single dose, split dose and fractionated radiation was compared to determine whether proliferative status was an important response determinant. The response of FRTL-5 cells was not influenced by proliferative status at the time of irradiation. Additionally, dose response was not altered by variable (12 hr-8 days) non-proliferative intervals before or after irradiation. As revealed by split dose experiments, the rate and extent of sublethal damage repair was likewise similar for proliferative and non-proliferative cells. Multifraction experiments employing three fractions separated by 6 hr intervals indicate that non-proliferative FRTL-5 cells completely repair sublethal damage between fractions. These results indicate that the radiation response of FRTL-5 cells is not influenced by the proliferative status of the cells prior to or post-irradiation.
- Research Organization:
- Univ. of Wisconsin, Madison (USA)
- OSTI ID:
- 5875006
- Journal Information:
- Int. J. Radiat. Oncol., Biol. Phys.; (United States), Vol. 16:6
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
THYROID CELLS
BIOLOGICAL RADIATION EFFECTS
CELL PROLIFERATION
CELL CYCLE
CELL FLOW SYSTEMS
DOSE-RESPONSE RELATIONSHIPS
EPITHELIUM
FRACTIONATED IRRADIATION
IN VITRO
RATS
THYROID
TSH
ANIMAL CELLS
ANIMAL TISSUES
ANIMALS
BIOLOGICAL EFFECTS
BODY
ENDOCRINE GLANDS
GLANDS
HORMONES
IRRADIATION
MAMMALS
ORGANS
PEPTIDE HORMONES
PITUITARY HORMONES
RADIATION EFFECTS
RODENTS
TISSUES
VERTEBRATES
560120* - Radiation Effects on Biochemicals
Cells
& Tissue Culture