Corneal NF-kappaB activity is necessary for the retention of transparency in the cornea of UV-B-exposed transgenic reporter mice.
To determine the dynamics of Nuclear Factor-kappaB (NF-kappaB) in murine corneal pathology and the role of NF-kappaB in maintaining corneal clarity after ultraviolet B radiation insult, transgenic mice containing NF-kappaB-luciferase reporter were exposed to LPS (bacterial lipopolysaccharide), TNF-alpha (Tumor Necrosis Factor-alpha) or 4 kJ m(-2) UV-B radiation. NF-kappaB decoy oligonucleotides were also administered in some of the UV-B experiments. Following various exposure times, the mice were sacrificed and whole eyes or corneal tissues were obtained. Whole eyes were examined for scattering using a point-source optical imaging technique. Tissue homogenates were examined for luciferase activity using a luminometer. TNF-alpha and LPS-injected NF-kappaB-luciferase transgenic mice demonstrated 3-10-fold increases in cornea NF-kappaB with peak activities at 4 and 6 hr post-injection, respectively. Mice exposed to 4 kJ m(-2) UV-B exhibited a 3-fold increase in NF-kappaB activity 4 hr post-exposure. The administration of NF-kappaB-decoy oligonucleotides to mice had the effect of reducing UV-B-induced NF-kappaB activity in the cornea and significantly increasing the amount of light scattering in UV-B exposed corneas 7 days post-UV-B exposure when compared to sham injected mice. These results indicate that NF-kappaB is activated in cornea in pathologies that involves increased plasma levels of LPS and TNF-alpha, as well as direct UV-B exposure, and suggest that NF-kappaB activation play an essential part in the corneal healing process.
Alexander
George
G
Department of Nutrition, Faculty of Medicine, University of Oslo, P.O. Box 1046, Blindern, 0316 Oslo, Norway. george.alexander@medisin.uio.no
Carlsen
Harald
H
Blomhoff
Rune
R
D000818:Animals; D003315:Cornea / Q000378:metabolism* / Q000528:radiation effects; D003318:Corneal Opacity / Q000378:metabolism*; D004307:Dose-Response Relationship, Radiation; D005136:Eye Proteins / Q000378:metabolism*; D007275:Injections, Intravenous; D008070:Lipopolysaccharides / Q000008:administration & dosage; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D016328:NF-kappa B / Q000378:metabolism*; D009841:Oligonucleotides / Q000008:administration & dosage; D018384:Oxidative Stress / Q000502:physiology; D012542:Scattering, Radiation; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000008:administration & dosage; D014466:Ultraviolet Rays
D005136:Eye Proteins; D008070:Lipopolysaccharides; D016328:NF-kappa B; D009841:Oligonucleotides; D014409:Tumor Necrosis Factor-alpha; D008156:Luciferases