Ultrastructural investigation of microcalcification and the role of @entity26 - XXXX deprivation in cultured rat hippocampal slices.

@entity24234 @entity2806 @entity1249 @entity12925 @entity26 @entity622 @entity730 @entity74 @entity460 @entity413
UNASSIGNED: Intracellular @entity460 accumulation is associated with cell death in several @entity74 including @entity2806 , but the exact mechanisms of @entity730 need to be clarified. We used organotypic hippocampal slice culture - cultures subjected to @entity26 - @entity413 deprivation (OGD) mimicking the in vivo situation to investigate the events underlying ectopic @entity730 . @entity622 staining indicating @entity460 deposition was observed in the cornu ammonis (CA)1 and dentate gyrus regions in control hippocampal slices despite no specific labeling for cell death markers. Electron microscopy using the @entity12925 / @entity24234 method revealed scattered degenerated cells throughout the normally appearing @entity1249 region. They contained electron-dense precipitates within mitochondria, and electron probe microanalysis confirmed that they were calcifying mitochondria. Selective @entity460 deposition was noted within, but not beyond, mitochondria in these mineralized cells. They showed ultrastructural features of non-necrotic, non-apoptotic cell death and retained their compact ultrastructure, even after the majority of mitochondria were calcified. Unexpectedly, no intracellular @entity730 was noted in necrotic @entity1249 pyramidal cells after OGD, and there was no progression of @entity730 in OGD-lesioned slices. In addition, mineralized cells in both control and OGD-lesioned slices were closely associated with or completely engulfed by astrocytes but not microglia. These astrocytes were laden with heterogeneous cytoplasmic inclusions that appeared to be related with their phagocytic activity. These data demonstrate that microcalcification specifically associated with mitochondria might lead to a novel type of cell death and suggest that astrocytes may be involved in the phagocytosis of these mineralized cells and possibly in the regulation of ectopic @entity730 .
