title: Protective effects of melatonin against oxidation of guanine bases in DNA and decreased microsomal membrane fluidity in rat liver induced by whole body ionizing radiation.
abstract: The aim of the study was to examine the potential protective effect of melatonin against whole body ionizing radiation (800 cGy). Changes in 8-hydroxy-2'-deoxyguanosine (8-OH-dG) levels, an index of DNA damage, and alterations in membrane fluidity (the inverse of membrane rigidity) and lipid peroxidation in microsomal membranes, as indices of damage to lipid and protein molecules in membranes, were estimated. Measurements were made in rat liver, 12 h after their exposure to radiation. To test the potential protective effects of melatonin, the indole was injected (i.p. 50 mg/kg b.w.) at 120, 90, 60 and 30 min prior to radiation exposure. Both 8-OH-dG levels and microsomal membrane rigidity increased significantly 12 h after radiation exposure. Melatonin completely counteracted the effects of ionizing radiation. Changes in 8-OH-dG levels and membrane fluidity are early sensitive parameters of DNA and microsomal membrane damage, respectively, induced by ionizing radiation and our findings document the protective effects of melatonin against ionizing radiation.
authors.affiliation: Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio 78229-3900, USA.
authors.forename: M
authors.initials: M
authors.lastname: Karbownik
authors.forename: R J
authors.initials: RJ
authors.lastname: Reiter
authors.forename: W
authors.initials: W
authors.lastname: Qi
authors.forename: J J
authors.initials: JJ
authors.lastname: Garcia
authors.forename: D X
authors.initials: DX
authors.lastname: Tan
authors.forename: L C
authors.initials: LC
authors.lastname: Manchester
authors.lastname: Vijayalaxmi
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000818:Animals; D004247:DNA / Q000378:metabolism; D004249:DNA Damage; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000378:metabolism*; D015227:Lipid Peroxidation; D008099:Liver / Q000187:drug effects / Q000528:radiation effects*; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D008550:Melatonin / Q000494:pharmacology*; D008560:Membrane Fluidity / Q000187:drug effects / Q000528:radiation effects*; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D014916:Whole-Body Irradiation
chemical_list: D008315:Malondialdehyde; D000080242:8-Hydroxy-2'-Deoxyguanosine; D004247:DNA; D003849:Deoxyguanosine; D008550:Melatonin