Prooxidant-antioxidant balance in rats under hypothermia combined with modified hemoglobin-oxygen affinity

Deep hypothermia (fall of body temperature by more than 10degreesC) is associated with the serious perturbation of oxygen delivery and body prooxidant-antioxidant balance. The blood oxygen-binding properties determine the conditions of oxygen diffusion to tissues and the values of tissue PO2 and have a specific role in the complex system of antioxidant defense. Our aim was to evaluate the prooxidant-antioxidant balance under the conditions of modified hemoglobin-oxygen affinity (HOA) in a rat experimental model of hypothermia (HOA was increased by sodium cyanate (NaOCN) and decreased by sodium o-iodobenzoate (OISB)). The preliminary shift of oxyhemoglobin dissociation curve (ODC) leftwards during the hypothermia was accompanied by the shift of prooxidant-antioxidant balance towards activation of the lipid peroxidation (LPO), and the ODC shift rightwards was accompanied by the LPO lowering. HOA decrease is favorable during the deep hypothermia due to the optimized oxygen flux to tissues and its lower fraction spent for the free radical reactions that is associated with the less marked distresses of prooxidant-antioxidant balance. (C) 2002 Elsevier Science Ltd. All rights reserved.