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The effects of radioprotectant amifostine on irradiated rat brain and liver tissues

Çakmak, Gülgün
Amifostine is the only approved radioprotective agent by the Food and Drug Administration for reducing the damaging effects of radiation on healthy tissues. In this study, the effects of ionizing radiation on rat liver microsomal membrane and brain tissue and the protecting effects of amifostine on these systems were investigated at molecular level. Sprague-Dawley rats, which were administered amifostine or not, were whole-body irradiated and liver microsomal membranes and different regions of the brain of these rats were analyzed using FTIR spectroscopy, FTIR microspectroscopy and synchrotron FTIR microspectroscopy. The first part of this study revealed that ionizing radiation caused a decrease in the total lipid content and CH2 groups of lipids, an increase in the carbonyl esters, olefinic=CH and CH3 groups of lipids in the white matter and grey matter regions of the brain, which could be interpreted as a result of lipid peroxidation. In addition, radiation altered the protein structure of the brain. Amifostine caused significant protective effect against all the radiation induced damages in the brain. In the second part of the study, FTIR results showed that radiation induced a decrease in the lipid/protein ratio and a degradation of lipids into smaller fragments that contain less CH2 and more carbonyl esters, olefinic=CH and CH3 groups in microsomal membranes. In addition, radiation caused an alteration in the secondary structure of proteins, an increase in lipid order and a decrease in the membrane dynamics. Amifostine prevented all the radiation induced compositional, structural and functional damages in the liver microsomal membranes.