FATTY-ACID COMPOSITION OF PLASMA-LIPIDS AND ERYTHROCYTE-MEMBRANES DURING SIMULATED EXTRAVEHICULAR ACTIVITY

Ten subjects (from 27 to 41 years) have been participated in 32 experi ments. They were decompressed from ground level to 40-35 kPa in altitu de chamber when breathed 100% oxygen by mask and performed repeated cy cles of exercises (3.0 Kcal/min). The intervals between decompressions were 3 - 5 days. Plasma lipid and erythrocyte membrane fatty acid com position was evaluated in the fasting venous blood before and immediat ely after hypobaric exposure. There were 7 cases decompression sicknes s (DCS). Venous gas bubbles (GB) were detected in 27 cases (84.4%). An y significant changes in the fatty acid composition of erythrocyte mem branes and plasma didn't practically induce after the first decompress ion. However, by the beginning of the second decompression the total l ipid level in erythrocyte membranes decreased from 54.6 mg% to 40.4 mg % in group with DCS symptoms and from 51.2 mg% to 35.2 mg% (p<0.05) wi thout DCS symptoms. In group with DCS symptoms a tendency to increased level of saturated fatty acids in erythrocyte membranes (16:0, 18:0), the level of the polyunsaturated linoleic fatty acid (18:2) and arach idonic acid (20:4) tended to be decreased by the beginning of the seco nd decompression. Insignificant changes in blood plasma fatty acid com position was observed in both groups. The obtained biochemical data th at indicated the simulated extravehicular activity (EVA) condition is accompanied by the certain changes in the blood lipid metabolism, stru ctural and functional state of erythrocyte membranes, which are revers ible. The most pronounced changes are found in subjects with DCS sympt oms. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.