title: Cytosolic labile zinc: a marker for apoptosis in the developing rat brain.
abstract: Cytosolic zinc accumulation was thought to occur specifically in neuronal death (necrosis) following acute injury. However, a recent study demonstrated that zinc accumulation also occurs in adult rat neurons undergoing apoptosis following target ablation, and in vitro experiments have shown that zinc accumulation may play a causal role in various forms of apoptosis. Here, we examined whether intraneuronal zinc accumulation occurs in central neurons undergoing apoptosis during development. Embryonic and newborn Sprague-Dawley rat brains were double-stained for terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling (TUNEL) detection of apoptosis and immunohistochemical detection of stage-specific neuronal markers, such as nestin, proliferating cell nuclear antigen (PCNA), TuJ1 and neuronal nuclear specific protein (NeuN). The results revealed that apoptotic cell death occurred in neurons of diverse stages (neural stem cells, and dividing, young and adult neurons) throughout the brain during the embryonic and early postnatal periods. Further staining of brain sections with acid fuchsin or zinc-specific fluorescent dyes showed that all of the apoptotic neurons were acidophilic and contained labile zinc in their cell bodies. Cytosolic zinc accumulation was also observed in cultured cortical neurons undergoing staurosporine- or sodium nitroprusside (SNP)-induced apoptosis. In contrast, zinc chelation with CaEDTA or N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) reduced SNP-induced apoptosis but not staurosporine-induced apoptosis, indicating that cytosolic zinc accumulation does not play a causal role in all forms of apoptosis. Finally, the specific cytosolic zinc accumulation may have a practical application as a relatively simple marker for neurons undergoing developmental apoptosis.
authors.affiliation: Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Joo-Yong
authors.initials: JY
authors.lastname: Lee
authors.forename: Jung Jin
authors.initials: JJ
authors.lastname: Hwang
authors.forename: Mi-Ha
authors.initials: MH
authors.lastname: Park
authors.forename: Jae-Young
authors.initials: JY
authors.lastname: Koh
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D001557:Benzenesulfonates; D015415:Biomarkers / Q000378:metabolism; D001921:Brain / Q000166:cytology* / Q000196:embryology / Q000502:physiology; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism*; D004622:Embryo, Mammalian; D004791:Enzyme Inhibitors / Q000633:toxicity; D005453:Fluorescence; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D007150:Immunohistochemistry / Q000379:methods; D020287:In Situ Nick-End Labeling / Q000379:methods; D007381:Intermediate Filament Proteins / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D051379:Mice; D009419:Nerve Tissue Proteins / Q000378:metabolism; D064231:Nestin; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D009599:Nitroprusside / Q000633:toxicity; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D019311:Staurosporine / Q000633:toxicity; D014404:Tubulin / Q000378:metabolism; D015032:Zinc / Q000378:metabolism*
chemical_list: D001557:Benzenesulfonates; D015415:Biomarkers; D004791:Enzyme Inhibitors; D005904:Glial Fibrillary Acidic Protein; D007381:Intermediate Filament Proteins; D009419:Nerve Tissue Proteins; C577485:Nes protein, mouse; C577486:Nes protein, rat; D064231:Nestin; D018809:Proliferating Cell Nuclear Antigen; D014404:Tubulin; D009599:Nitroprusside; C086337:acid fuchsin; D007770:L-Lactate Dehydrogenase; C505409:Casp3 protein, mouse; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases; D010751:Phosphopyruvate Hydratase; D019311:Staurosporine; D015032:Zinc