Mitochondrial cytochrome c release in radiation-induced apoptosis of human peripheral T cells.
We examined sequential changes in post-irradiated peripheral blood T cells taken from normal volunteers, using a microscopy-video system, mitochondrial membrane potential assay, annexin V, propidium iodide, and cytochrome c ELISA kit. After 5 Gy irradiation with 10 MV X-ray from a linear accelerator, the percentages of apoptotic T cells were estimated as approximately 5, 10, 20, 35, and 70%, at 0, 3, 6, 10, and 20 h after irradiation, respectively, as observed with the microscopy-video system. Using a CCD camera-equipped fluorescence microscope and MitoCapture, a mitochondrial membrane potential indicator, approximately half of the T cells showed dysfunction of mitochondrial membrane potential at 10 h after 5 Gy irradiation. With regard to annexin V and propidium iodide, approximately 40 and 5% of the human peripheral T cells showed positivity against annexin V and propidium iodide at that time, respectively. Mitochondrial cytochrome c release from the mitochondria to the cytosol was confirmed to start at 10 h and to reach a maximum at 20 h after 5 Gy of irradiation. These results demonstrated that mitochondrial cytochrome c release occurred following dysfunction of mitochondrial membrane potential in radiation-induced T cell apoptosis.
Ogawa
Yasuhiro
Y
Department of Radiology, Kochi Medical School, Oko-cho, Nankoku-shi, Japan. ogaway@kochi-ms.ac.jp
Nishioka
Akihito
A
Kobayashi
Toshihiro
T
Kariya
Shinji
S
Hamasato
Shinji
S
Saibara
Toshiji
T
Nakayama
Koichi
K
Seguchi
Harumichi
H
Yoshida
Shoji
S
D017304:Annexin A5 / Q000494:pharmacology; D017209:Apoptosis; D004396:Coloring Agents / Q000494:pharmacology; D003574:Cytochrome c Group / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004307:Dose-Response Relationship, Radiation; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D008564:Membrane Potentials; D008856:Microscopy, Fluorescence; D018715:Microscopy, Video; D008928:Mitochondria / Q000378:metabolism*; D011419:Propidium / Q000494:pharmacology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D013601:T-Lymphocytes / Q000378:metabolism* / Q000528:radiation effects*; D013997:Time Factors
D017304:Annexin A5; D004396:Coloring Agents; D003574:Cytochrome c Group; D018076:DNA, Complementary; D019253:Proto-Oncogene Proteins c-bcl-2; D011419:Propidium