| Autor: | Henry L. Bart, Jr, Peter J. Martinat, Assaf Abdelghani, Paul B. Tchounwou, S. Lavern Taylor |
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| Rok vydání: | 1998 |
| Předmět: | |
| Zdroj: | Ecotoxicology. 7:325-334 |
| ISSN: | 0963-9292 |
| DOI: | 10.1023/a:1012034804535 |
| Popis: | Alterations in intracellular free calciumconcentration ([Ca2+]i) areinstrumental in apoptosis. We have previously shown that a[Ca2+]i increase above 1000 nM isrelated to the appearance of apoptosis in serum-free cultures ofgranulosa cell sheets. In the present study we examined how the[Ca2+]i increase relates toindicators of distinct phases of the apoptotic cascade. We used adouble staining technique whereby loading with theCa2+ indicator fura-2 and capture of a[Ca2+]i image, was followed bystaining with annexin-V, as an early apoptotic marker or withacridine orange, marking the late degradation phase. Calcium imagingshowed a large heterogeneity of cellular[Ca2+]i levels. [Ca2+]i was moderately increased to∼230 nM in annexin positive cells but was at resting levelin cells with nuclear manifestations of apoptosis as evidenced byacridine orange. Our results suggest that a moderate[Ca2+]i increase is related tophosphatidylserine translocation and that[Ca2+]i has already recovered inapoptotic cells displaying chromatin condensation and/or nuclearfragmentation. Granulosa cells with[Ca2+]i above 1000 nM were neverobserved to stain positive for the apoptotic markers used; therefore,large [Ca2+]i increases areprobably related to the apoptosis initiation phase occurring upstreamof phosphatidylserine exposure. |
| Databáze: | OpenAIRE |
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