Enriched astrocytic cultures also respond to GC with moderate activation of caspase 3, but fail to show signs of early- or late-stage apoptosis.

<p>After re-plating, enriched astrocytic cultures were treated with GC (48 h) in medium containing either charcoal-stripped serum (data not shown) or B27 supplement (representative images in <b>A–L</b>). Enriched astrocytes responded to GC treatment DEX with moderately increased immunostaining for activated caspase 3; these cells did not enter late-stage (stage II) apoptosis, as shown by TUNEL (<b>A–F</b>). In contrast, staurosporine (STA) induced a marked activation of caspase 3 and apoptosis (<b>G–I</b>). The immunocytochemical results shown for activated caspase 3 in <b>A–I</b> were confirmed by immunoblotting (J). Staurosporine, but not GC, treatment of enriched astrocytic cultures significantly increased levels of immunoreactive phospho-H2A.X, a marker of early apoptosis, as shown by immunoblotting studies (<b>K</b>). Similarly, astrocytes exposed to STA, but not GC, displayed high molecular weight (HMW) DNA fragments, when lysates where subjected to pulse-field gel electrophoresis (PFGE) (<b>L</b>); all lanes were loaded with DNA from the same number of astrocytes, and arrow indicates 50 kb HMW DNA fragments. Scale bars: 50 µm.