title: Antioxidative enzymes in irradiated rat brain-indicators of different regional radiosensitivity.
abstract: OBJECTIVE
  Previously, we examined manganese superoxide dismutase (MnSOD), copper-zinc superoxide dismutase (CuZnSOD), and catalase (CAT) activities in rat brain irradiated with 2 or 3 Gy of γ-rays. The results indicated that lower MnSOD activity and inducibility found in hippocampus might explain higher radiosensitivity of this brain region. Thus, in this study, we wanted to determine changes of MnSOD, CuZnSOD, and CAT activities after dose of 5 Gy and to find out if differences in MnSOD activity are caused by changes in its expression.
  
  
  METHODS
  Heads of 4-day-old female rats were irradiated with γ-rays, using (60)Co. Animals were sacrificed 1/24 h after exposure. Hippocampus and cortex tissues were prepared for enzyme activity measurements and Western blot analysis.
  
  
  RESULTS
  One hour after exposure, γ-rays significantly decreased MnSOD activity in both examined brain regions. Twenty-four hours later, MnSOD recovery showed dose and regional dependence. It was weaker at higher doses and in hippocampal region. MnSOD expression changed in the similar manner as MnSOD activity only at lower doses of γ-rays. In both examined brain regions, gamma radiation significantly decreased CuZnSOD activity and did not change activity of CAT.
  
  
  CONCLUSIONS
  Our results confirmed that MnSOD plays an important role in different regional radiosensitivity but also showed that depending on dose, radiation affects MnSOD level by utterly different mechanisms. Postradiation changes of CuZnSOD and CAT are not regionally specific and therefore, cannot account for the different radiosensitivity of the hippocampus and cortex.
authors.affiliation: Laboratory of Molecular Biology and Endocrinology, Vinča Institute of Nuclear Sciences, University of Belgrade, PO Box 522, 11001, Belgrade, Serbia. anato@vinca.rs.
authors.forename: Ana
authors.initials: A
authors.lastname: Todorović
authors.affiliation: Laboratory of Molecular Biology and Endocrinology, Vinča Institute of Nuclear Sciences, University of Belgrade, PO Box 522, 11001, Belgrade, Serbia.
authors.forename: Snežana
authors.initials: S
authors.lastname: Pejić
authors.affiliation: Laboratory of Molecular Biology and Endocrinology, Vinča Institute of Nuclear Sciences, University of Belgrade, PO Box 522, 11001, Belgrade, Serbia.
authors.forename: Vesna
authors.initials: V
authors.lastname: Stojiljković
authors.affiliation: Laboratory of Molecular Biology and Endocrinology, Vinča Institute of Nuclear Sciences, University of Belgrade, PO Box 522, 11001, Belgrade, Serbia.
authors.forename: Ljubica
authors.initials: L
authors.lastname: Gavrilović
authors.affiliation: Laboratory of Molecular Biology and Endocrinology, Vinča Institute of Nuclear Sciences, University of Belgrade, PO Box 522, 11001, Belgrade, Serbia.
authors.forename: Nataša
authors.initials: N
authors.lastname: Popović
authors.affiliation: Laboratory of Molecular Biology and Endocrinology, Vinča Institute of Nuclear Sciences, University of Belgrade, PO Box 522, 11001, Belgrade, Serbia.
authors.forename: Ivan
authors.initials: I
authors.lastname: Pavlović
authors.affiliation: Department of Physiology, Institute for Biological Research "Siniša Stanković", University of Belgrade, 11060, Belgrade, Serbia.
authors.forename: Zorica S
authors.initials: ZS
authors.lastname: Saičić
authors.affiliation: Laboratory of Molecular Biology and Endocrinology, Vinča Institute of Nuclear Sciences, University of Belgrade, PO Box 522, 11001, Belgrade, Serbia.
authors.forename: Snežana B
authors.initials: SB
authors.lastname: Pajović
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000033:anatomy & histology / Q000201:enzymology* / Q000528:radiation effects*; D002374:Catalase / Q000378:metabolism*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D011836:Radiation Tolerance / Q000528:radiation effects; D051381:Rats; D013482:Superoxide Dismutase / Q000378:metabolism*; D013997:Time Factors
chemical_list: D002374:Catalase; D013482:Superoxide Dismutase
keywords: Brain; CAT; Cortex; Hippocampus; Radiosensitivity; SOD