[Calcium homeostasis in the thymocyte apoptosis II. Accumulation of calcium in mitochondria and endoplasmic reticulum].
The activity of energy-dependent Ca2+-accumulation systems in rat thymocytes mitochondria and endoplasmic reticulum (ER) in control and at the early stage of X-irradiation or H2O2-induced apoptosis were determined in experiments using the model of digitonin-permeabilized cells with addition of thapsigargin and ruthenium red. The mitochondrial Ca2+-transporting system proved to be more sensitive to both apoptotic stimuli. The stationary level of Ca2+, accumulated in mitochondria and initial rate of Ca2+ accumulation in ER were reduced 15 min after H2O2 treatment. The parameters of mitochondrial Ca2+-accumulation system in irradiated cells were decreased 30 min after irradiation. Cyclosporin A almost completely inhibited DNA fragmentation in irradiated and partly--in peroxide-treated cells. The mitochondrial calcium homeostasis imbalance is suggested to be an early event in thymocytes apoptosis initiation.
Grebinyk
D M
DM
Griniuk
I I
II
Matyshevskaia
O P
OP
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D004072:Digitonin / Q000494:pharmacology; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D006706:Homeostasis / Q000187:drug effects / Q000528:radiation effects; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D051381:Rats; D017208:Rats, Wistar; D013950:Thymus Gland / Q000166:cytology / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D014965:X-Rays
D006861:Hydrogen Peroxide; D004072:Digitonin; D002118:Calcium