@misc{oai:repo.qst.go.jp:00080772,
 author = {伊原, 智一 and 野口, 実穂 and 岡部, 弘基 and 横谷, 明徳 and Ihara, Tomokazu and Noguchi, Miho and Yokoya, Akinari},
 month = {Oct},
 note = {Cell-cycle of senescent cells is irreversibly arrested in G1 phase. These cells show some peculiar characteristics such as senescence associated secretary phenotype (SASP) or SA-βgal positive. These evidences suggest that intracellular environment of senescent cells might be different from those of viable (normal) cells. Cellular temperature would be a promising parameter representing intracellular environment and is known to fluctuate in a cell cycle dependent manner. For example, temperature of nucleus is 0.7 ℃ higher than cytoplasm in G1 phase cells, whereas nucleic and cytoplasmic temperatures are almost in a similar level for S/G2 phase [1]. It is likely that the temperature depends on heat balances of chemical reactions of metabolisms, and could be different among subcellular organelles according to their activities in particular cell cycle. To verify whether cellular temperature correlated with senescence, we performed measurements of the cellular temperature by introducing a chemical thermoprobe, Cellular Thermoprobe for Fluorescence Ratio, into immortalized human fibroblast cells, BJ-5ta. The temperature of senescent cells observed several days after exposure to 20 Gy X-rays was determined from the ratio of fluorescence intensity of two colors of the probe based on a calibration line. The obtained value was 58.1℃, which seemed too high as cellular temperature. There still might be some missing factors with our experimental procedures. Current situations and problems to be addressed for these experiments will be discussed.
[1] Okabe, K. et al. (2012) Nat. Commun. 3, 750, 日本放射線影響学会　第63回大会},
 title = {An approach of intracellular measurements of temperature in senescent cells after X-ray exposure.},
 year = {2020}
}