Free radical scavenging, DNA protection, and inhibition of lipid peroxidation mediated by uric acid.
Uric acid (UA) has been proposed to be the dominant antioxidant in birds. The objective of this study was to investigate the quenching effect of varying concentrations of UA, including those found in avian plasma, on specific reactive oxygen species (ROS) and to determine the ability of UA to protect DNA and cellular membranes from ROS-mediated damage. Hydroxyl (OH) and superoxide (O2-) radicals were detected by electron spin resonance (ESR) and their presence was reduced following addition of UA (p <0.05) in a concentration-dependent manner. UA inhibited hydroxyl-mediated DNA damage, indicated by the presence of more precise, dense bands of lambda Hind III DNA after agarose gel electrophoresis and ethidium bromide staining (p <0.05). Lipid peroxidation of silica-exposed RAW 264.7 cell membranes was diminished (p <0.02) after addition of UA to the cell incubation mixture. These studies demonstrate that UA scavenges hydroxyl and superoxide radicals and protects against DNA damage and lipid peroxidation. These results indicate specific antioxidant protection that UA may afford birds against ROS-mediated damage.
Stinefelt
Beth
B
Division of Animal and Veterinary Science, West Virginia University, Morgantown, West Virginia 26506, USA.
Leonard
Stephen S
SS
Blemings
Kenneth P
KP
Shi
Xianglin
X
Klandorf
Hillar
H
D000818:Animals; D004249:DNA Damage / Q000187:drug effects*; D004578:Electron Spin Resonance Spectroscopy; D016166:Free Radical Scavengers / Q000494:pharmacology*; D017665:Hydroxyl Radical / Q000032:analysis; D015227:Lipid Peroxidation / Q000187:drug effects*; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000502:physiology; D051379:Mice; D015183:Restriction Mapping; D013481:Superoxides / Q000032:analysis; D014527:Uric Acid / Q000494:pharmacology*
D016166:Free Radical Scavengers; D013481:Superoxides; D014527:Uric Acid; D017665:Hydroxyl Radical