Analysis of Intracellular Mitochondrial Activity Following Hyperthermia and Irradiation

温熱処理及び放射線照射にともなう細胞内ミトコンドリア活性の変動

Analysis of Intracellular Mitochondrial Activity Following Hyperthermia and Irradiation

Creators Karino Yuichi

Intracellular mitochondrial activity(Rhodamine-123 uptake) and DNA content distribution of L-5 cells and HeLa S3 cells after hyperthermia or irradiation were measured by flow cytometry (FCM), and simultaneously relation between cell cycle and mitochondrial activity was examined. The results obtained were as follows: 1. In HeLa S3 cells, heat treatment at 43℃ for 60 min caused the accumulation of cells in the G_2+M phase and a decrease in the fraction of G_1 phase cells to 18 hrs. On the other hand , at 43℃ for 120 min such changes in the G_2+M and G_1 phase cells during 30 hrs were observed. Intracellular fluorescent intensity (Rhodamine-123 uptake) is gradually increased, reached to a peak at 18 hrs after heating at 43 ℃ for 60 min and increased continuously during 30 hrs after heating at 43℃ for 120 min. 2. In L-5 cells, heat treatment at 42℃ for 30 min caused the accumulation of cells in the S phase and a decrease in the fraction of G_1 phase cells to 9 hrs after treatment, but Rho-123 uptake was relatively constant. On the contrary, at 43℃ 30 min the changes in the DNA distribution of the cell population were not observed, but Rho-123 uptake was markedly decrease at the time of 9 hrs , then gradually increased. 3. In HeLa S3 cells, 5Gy irradiation caused the accumulation of cells in the S and G_2+M phases, and a decrease of G_1 phase cell to 12 hrs after irradiation. Ten Gy irradiation caused decrease of G_1 fraction to 15 hrs and cell accumulation of G2+M fraction to 18 hrs. It was observed that G2+M cells were accumulated after irradiation and mitochondrial activities reached to maximum level at that time. 4. In L-5 cells, at the both of 5 and 10 Gy irradiation, the accumulation of cells in the G2+M fraction was shown and a decrease of S fraction was observed from 9 hrs after irradiation. At the both of irradiation dose, Rho-123 uptake gradually increased during 6 to 15 hrs , and at 10 Gy irradiation to 36 hrs continuously increased. In these results, it is suggested close correlation may exist between the changes of mitochondrial activity and cell cycle, especially between mitochondrial activity and cell damage induced by heating.

[ISSN]0513-1731

[NCID]AN00243156