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Nick: ladyvivi
Oggetto: permettetemi...
Data: 19/10/2006 22.31.48
Visite: 737
un momento "autocelebrativo"....
CARDIAC ISCHAEMIA: IRON METABOLISM IN CARDIOMIOCYTES DURING HYPOXIA
Virginia Cozzolino, Carmen Maffettone, Maria Gabriella Dattolo, Guglielmo Busiello, Carlo Irace, Rita Santamaria and Alfredo Colonna
Dipartimento di Farmacologia Sperimentale, Università di Napoli "Federico II", Via D. Montesano, 49, 80131 Napoli
INTRODUCTION: Cardiac ischemia occurs after reduction of blood flow with consequent cardiac tissue damage. Riperfusion causes oxygen reactive species (ROS) production, which react with various molecules leading to oxidative cell damage. Oxygen and iron metabolism are linked because hypoxia and free iron intracellular concentration are the main causes of cell death since iron can catalyze ROS production. Cells use an efficient system to regulate iron homeostasis in order to limitate iron toxicity by the activity of regulatory proteins (IRPs), which act post-transcriptionally on ferritin and transferrin receptor (Tfr) mRNA, regulating their translation. Aim of this work is to evaluate the activity and expression of the main proteins involved in iron metabolism and the correlation with cell viability in cardiomiocytes exposed to hypoxia/reoxygenation.
MATERIALS AND METHODS: Cardiomiocytes of rat embryo (H9c2) are exposed to combined oxygen and glucose deprivatization (OGD) for variable times, as previously reported (1). Cells viability is assessed by MTT assay and cellular energetic state by dosing ATP levels. ROS production is measured with a fluorescent probe and lipoperoxidation products by TBARs test. Ferritin, Tfr, IRPs and caspase-3 expression is analyzed by Western blot and IRPs RNA-binding activity by EMSA.
RESULTS: OGD treatments determine a divergent modulation of RNA-binding of IRPs (IRP1 activity decreases and IRP2 increases), without affecting IRPs protein content. These effects are partially reverted by reoxygenation. Moreover, TfR expression decreases during OGD and enhances after reoxygenation, whereas ferritin levels result unchanged in OGD exposure and increase only during the early reoxygenation. Cardiomiocytes mithocondrial activity and ATP production progressively decrease after OGD exposure, returning to basal values during the subsequent reoxygenation, except for OGD longer than 10h. In addition, ROS production and lipoperoxidation increase, particularly in the early reoxygenation phase. Since any apoptosis feature is detectable, these results suggest that prolonged OGD treatments result in necrotic cell death.
1. C. Irace et al. (2005), J. Neurochem. 95, 1321-1333
Work supported by grants from COFIN 2004 and Regione Campania L.R. 5/02 2003
primo nomeeeee e vai.....!!!!
queste so soddisfazioni....
ps...per i non addetti ai lavori...è l'abstract di un lavoro scientifico del quale sono autrice....è un successone per me:)!!!
