PROTECTION FROM ARACHIDONIC ACID-INDUCED SUDDEN DEATH BY INJECTION OF TRIDOCOSAHEXAENOYL-GLYCEROL EMULSION INTO RABBITS
An injectable emulsion of docosahexaenoic acid (DHA) was prepared. One hundred ml of the emulsion contained 3g of 93%-pure 1,2,3-tridocosahexaenoy1-glycerol (DHA-TG), 1.2g of 93%-pure 2-docosahexaenoyl-phosphatidylcholine as an emulsifier and 2.5g of glycerol. Thirty ml of the emulsion of DHA-TG was injected into rabbits on days 1 and 4 of the study. Blood was taken on day 0, on day 4 just before the second injection, and on day 7. The percent of DHA in the total phospholipid fraction of platelets was increased from 0.46% (day 0) to 1.88% (day 4, p<0.05) and 3.66% (day 7; p<0.02 vs day 0); that of eicosapentaenoic acid (EPA) was increased from 0.46% (day 0) to 1.03% (day 4, p<0.02) and 1.63% (day 7; p< 0.05 vs day 0); that of arachidonic acid (AA) was decreased from 9.45% (day 0) to 4.31% (day 4, p<0.05) and 6.68% (day 7; p<0.02 vs day 0). The percent of DHA in the total phospholipid fraction of erythrocyte membranes was increased from 0.23% (day 0) to 0.91% (day 4, p<0.05) and 1.52% (day 7; p<0.005 vs day 0); that of EPA was increased from 0.21% (day 0) to 0.34% (day 4, p<0.005) and 0.52% (day 7, p<0.01 vs day 0); that of AA was unchanged at all. Blood lipids were the same before and after the two injections of the emulsion, except that free fatty acids decreased markedly from 0.32 to 0.06 mEq/1 (p<0.02). On day 8, free AA (2 mg/Kg) was injected into ear veins of the treated three rabbits and also into those of four control rabbits, which were not treated with DHA-TG. All the control rabbits died a few minutes after the AA injection but none of DHA-treated rabbits died after AA injection (p<0.01). An emulsion of DHA-TG may be useful for patients having immediate risk of thrombosis or for those who need DHA but cannot take it orally.