Hypoxia-induced caspase-3 activation and DNA fragmentation in cortical neurons of newborn piglets: Role of nitric oxide

• Published in: Neurochemical research Vol. 28; no. 9; pp. 1351 - 1357
• Main Authors: PARIKH, N. A, KATSETOS, C. D, ASHRAF, Q. M, HAIDER, S. H, LEGIDO, A, DELIVORIA-PAPADOPOULOS, M, MISHRA, O. P
• Format: Journal Article
• Language: English
• Published: New York, NY Springer 01.09.2003; Springer Nature B.V
• Subjects: Adenosine Triphosphate - metabolism; Animals; Animals, Newborn; Biological and medical sciences; Caspase 3; Caspases - metabolism; Cerebral Cortex - enzymology; Cerebral Cortex - metabolism; Cerebral Cortex - pathology; DNA Fragmentation; Electrophoresis, Agar Gel; Enzyme Activation; Fundamental and applied biological sciences. Psychology; Hypoxia - enzymology; Hypoxia - metabolism; Hypoxia - pathology; Immunohistochemistry; Neurons - enzymology; Neurons - metabolism; Neurons - pathology; Nitric Oxide - metabolism; Phosphocreatine - metabolism; Swine; Vertebrates: nervous system and sense organs; immunoreactivity; Oxygen; Enzyme; Cysteine endopeptidases; Caspase; Environmental factor; neuronal nitric oxide synthase; Activation; Caspase-3; Nitric-oxide synthase; Peptidases; Neuron; Newborn animal; Nitric oxide; DNA; labeling index; Hydrolases; Hypoxia; Oxidoreductases
• ISSN: 0364-3190; 1573-6903
• DOI: 10.1023/A:1024992214886

Hypoxia results in generation of nitric oxide (NO) free radicals, activation of caspase-3, and genomic DNA fragmentation. The present study tests the hypothesis that hypoxia-induced caspase-3 activation and DNA fragmentation are nitric oxide mediated. Studies were conducted in newborn piglets, divided into normoxic (n = 5), hypoxic (n = 5), and hypoxic-7-NINA (n = 6). Hypoxic-7-NINA group received the neuronal nitric oxide synthase inhibitor, 7-Nitroindazole (7-NINA). Caspase-3 activity was determined spectrofluorometrically using enzyme-specific substrates. Sections from the neocortex were stained with an antiserum recognizing active caspase-3. Purified DNA was separated by gel electrophoresis. Administration of 7-NINA resulted in decreased immunoreactivity of caspase-3 (mean LI: 20.2%) as compared to the untreated hypoxia group (mean LI: 57.5%) (P < 0.05). 7-NINA attenuated caspase-3 enzymatic activity as well in comparison to the untreated hypoxia group (P < 0.05). Furthermore, multiple low molecular weight bands corresponding to DNA fragments were present in the hypoxic but not in the normoxic or hypoxic-7-NINA groups. Inhibition of nNOS abates the hypoxia-induced increase in active caspase-3 immunoreactivity, as well as enzymatic activity in cortical neurons, and DNA fragmentation in brain homogenates. We conclude that the coordinate increase of capase-3 activity and fragmentation of nuclear DNA in the hypoxic newborn piglet brain are NO mediated.