Radiation Protection by Exogenous Arachidonic Acid and Several Metabolites
Based on the observations that 16, 16-dimethyl prostaglandin E2 (dm PGE2) protected intestinal clonogenic cells (ICC) from some degree of radiation injury, studies were done to see if exogenous arachidonic acid (AA) and its products were radioprotectants. One mg AA was required to measure protection that increased ICC survival from a single dose of 15.0 Gy cesium-137 from about 9 to 21 cells per jejunal circumference (P < 0.001). With phospholipase A2, lower doses of AA were protective. All prostaglandins (PG’s) were protective with the exception of E1. PGI2 was the most protective natural PG (300% increase in survival), and 15-deoxy, 16-hydroxy,16-methyl PGE1 (misoprostol) was the most protective to date (600% over controls). 16, 16-dm PGE2 also protected ICC from some degree of injury by the high-energy neutrons of Fermilab. Of the leukotrienes (LT’s) tested, LTC4 was the most protective (about 250% above controls) and LTD4 was next in order (150% increase in survival). These results suggest that AA and products of the AA cascade can modify the response of tissue to radiation, which may have both mechanistic and clinical implications.
KeywordsArachidonic Acid Radiation Protection Radiation Injury Arachidonic Acid Cascade Cell Survival Curve
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