Effect of Hyperoxia on Serine Phosphorylation of Apoptotic Proteins in Mitochondrial Membranes of the Cerebral Cortex of Newborn Piglets

• Published in: Neurochemical research 2009-07, Vol.34 (7), p.1219-1225
• Main Authors: Brutus, Nadege A., Hanley, Sarah, Ashraf, Qazi M., Mishra, Om P., Delivoria-Papadopoulos, Maria
• Format: Article
• Language: English
• Subjects: Animals; Animals, Newborn; Apoptosis - drug effects; Apoptosis - physiology; bcl-2-Associated X Protein - metabolism; bcl-Associated Death Protein - metabolism; bcl-X Protein - metabolism; Biochemistry; Biomedical and Life Sciences; Biomedicine; Cell Biology; Cerebral Cortex - drug effects; Cerebral Cortex - metabolism; Cerebral Cortex - ultrastructure; Hyperoxia - physiopathology; Mitochondrial Membranes - metabolism; Neurochemistry; Neurology; Neurosciences; Original Paper; Phosphorylation; Proto-Oncogene Proteins c-bcl-2 - metabolism; Serine - metabolism; Swine
• ISSN: 0364-3190; 1573-6903
• DOI: 10.1007/s11064-008-9898-z

Previous studies have shown that hyperoxia results in cerebral cortical neuronal apoptosis. Studies have also shown that phosphorylation of anti-apoptotic proteins Bcl-2 and Bcl-xl results in loss of their anti-apoptotic potential leading to alteration in mitochondrial membrane permeability and the release of apoptogenic proteins in the neuronal cell of the newborn piglets. The present study tests the hypothesis that cerebral hyperoxia will result in increased serine phosphorylation of apoptotic proteins Bcl-2, Bcl-xl, Bax, and Bad in the mitochondrial membranes of the cerebral cortex of newborn piglets. Twelve newborn piglets were divided into normoxic (Nx, n  = 6) exposed to an FiO 2 of 0.21 for 1 h and hyperoxic (Hyx, n  = 6) exposed to FiO 2 of 1.0 for 1 h. In the Hyx group, PaO 2 was maintained above 400 mmHg while the Nx group was kept at 80–100 mmHg. Cerebral cortical tissue was harvested and mitochondrial fractions were isolated. Mitochondrial membrane proteins were separated using 12% SDS-PAGE, and probed with anti-serine phosphorylated Bcl-2, Bcl-xl, Bax, and Bad antibodies. Protein bands were detected, analyzed by imaging densitometry and density expressed as absorbance (OD × mm 2 ). Phosphorylated Bcl-2 (p-Bcl-2) protein density (OD × mm 2 ) was 81.81 ± 9.24 in Nx and 158.34 ± 10.66 in Hyx ( P