Bums Vol. 22, No. 4, pp. 291-294.1996 Copyright 0 1996 Elsevier Science Ltd for ISBI. All rights reserved Printed in Great Britain 0305-4179/96 $15.00+0.00 ELSEVIER Reduced erythrocyte deformability related to activated lipid peroxidation during the early postburn period G. Bekyarova I, T. Yankovaz, I. Kozarev’ and D. Yankov’ ‘Department of Pathophysiology and 2Department of Chemistry and Biochemistry, Medical University, Varna and 3Regional Hospital of Silistra, Silistra, Bulgaria The role of lipid peroxidation in reduced red cell defownabiliiy has been examined after thermal injury of rats #ull skin thickness over 15-20 per cenf of fatal body surface). An increased concentrafion of eryfhrocyte malonyldialdehyde (MDA) andblood thioburbiluric acid (7BA) reactive product levels during the first 3 days after thermal trauma was established. There was a remarkable decrease in red cell superoxide dismutase (SOD)activity after burns and an increase in glucose-6-phosphate dehydrogenase (G-6-PD) on day 3 postbum. 7he defomabiliry of eythrocytes wus diminished sign$cantly during the jirsf 3 days uffer burns. There was a signij?canf negafive correlation between the deformability and the amount of MDA accumulated in eythrocyfes (r = - 0.92). Both the accumulation of MDA and the reduction of SOD activity in eythrocytes were suppressed by alpha-focopherol treatment, which also prevented the decrease in erythrocyle deformability. 7hese results suggest that the activation of the peroxidative process is a possible mechanism for the decreased deformability of eythrocytes during the early stage after thermal injury. Copyright @) 1996 Elsevier Science Ltd for LSBI. Bums, Vol. 22, No. 4,291-294,1996 Introduction Microcirculatory disturbances and progressive hypoxia following thermal injury of the skin are closely related to rheological alterations in red blood cells and activation of lipid peroxidation1-4. Membrane peroxidative damagecan cause a decreasein deformability and life span of these blood cells in the microcirculation5*6. Red blood cells are protected against peroxidative damageby membraneand cytosol antioxidants’. Shortened survival of erythrocytes in burned patients, as well as in experimental models of thermal trauma, are related to high lipid peroxide levels in plasma,low glutathione peroxidase activity and reduced vitamin E content in these cells8*9. Data about the activity of other oxygen radical detoxifying enzymes such as superoxide dismutase (SOD) and glucoseQ-phosphate dehydrogenase (G-6-PD) in erythrocytes in the early period after bums, are rather contradictory9-“. It hasbeen reported that vitamin E has a protective effect on rheolo- gical properties of red blood cellslz. The aim of this study was to investigate the relationship between the deformability of erythrocytes and membrane oxidation during the early period after thermal trauma, using alpha-tocopherol (a-T) as a membraneantioxidant. Materials and methods Male Wistar rats weighing 220 f 18 g (mean f SD) were divided into three groups: (I) control, (2) burned untreated and (3) burned but treated with E-T. Animals were subjected to a 20 per cent total body surface area full thickness bum over the back and flanks by heat radiation, with a temperature of SO-6O”C, and an exposure of 8 s. Before thermal trauma the rats were anaesthetized with thiopental (30 mg/kg body mass). Alpha-tocopherol (Serva, Germany) was injected intraperitoneally in a dose of 20mg/kg body mass,three times: immediately after thermal trauma, at 24 h and at 48 h after burning. Blood samples for analysis were taken from the jugular vein at 24 h. 48 h and 72 h after burning. Lipid peroxidation in erythrocytes was measured according to the method of Yagi13by estimating malonyl- dialdehyde (MDA), a secondary breakdown product of lipid peroxidation. The content of thiobarbituric acid (TBA) reactive MDA products in blood was determined by the method of Porter et a1.14 SOD activity in erythrocytes was measuredby the method of Misra and Fridovich15, G6-PD was assessed by the test kit (Blihringer, Germany). Deformability of erythrocytes was determined by the filtration test of Yankov et al.l6 The filtration element contained six-layered FN-4 filter paper. During the trial, a constant negative pressure of 58 mmHg (7.8 kPa) for 2 min was maintained. Pressuregradients ranging between 20 and 30 mmHg (2.8-4.0 kPa) imitating hydrodynamic con- ditions at the microcirculatory level was obtained between the single layers of the filtration element. Only the third, fourth and fifth filter papers are processed. The results obtained were processedto give the filtration coefficient proposed by Yankov et a1.l6 The resultswere processed by analysis of variance using Student’s f-criterion for statistical significance, aswell asby correlation analysis.