gamma-linolenic-acid and Necrosis

To evaluate the possible role of essential fatty acids, specifically gamma-linolenic and eicosapentaenoic acid, in the amelioration of early and late radiation damage to the skin.. Skin sites on the flank of 22-25 kg female large white pigs were irradiated with either single or fractionated doses (20 F/28 days) of beta-rays from 22.5 mm diameter 90Sr/90Y plaques at a dose rate of approximately 3 Gy/min. Essential fatty acids were administered orally in the form of two 'active' oils, So-1100 and So-5407, which contained gamma-linolenic acid and a mixture of that oil with eicosapentaenoic acid, respectively. Oils (1.5-6.0 ml) were given daily for 4 weeks prior, both 4 weeks prior and 10-16 weeks after, or in the case of one single dose study, just for 10 weeks after irradiation. Control animals received a 'placebo' oil, So-1129, containing no gamma linolenic acid or eicosapentaenoic acid over similar time scales before and after irradiation. Acute and late skin reactions were assessed visually and the dose-related incidence of a specific reaction used to compare the effects of different treatment schedules.. A reduction in the severity of both the early and late radiation reactions in the skin was only observed when 'active' oils were given over the time course of the expression of radiation damage. Prior treatment with oils did not modify the radiation reaction. A 3.0 ml daily dose of either So-1100 or So-5407 given prior to, but also after irradiation with single and fractionated doses of beta-rays produced the most significant modification to the radiation reactions, effects consistent with dose modification factors between 1.06-1.24 for the acute reactions of bright red erythema and/or moist desquamation, and of 1.14-1.35 for the late reactions of dusky/mauve erythema and dermal necrosis. There was the strong suggestion of an effect produced by the 'placebo' oil, So-1129, after higher daily doses of oil.. Essential fatty acids can modulate normal tissue reactions when given over the time when radiation damage is normally expressed. Dose modification factors suggest that a > or = 10% higher dose is required to produce the same level of normal tissue injury. Clinical application of selected essential fatty acids at appropriate doses may lead to a significant increase in the therapeutic gain in patients treated for cancer by radiotherapy.

Topics: Animals; Beta Particles; Eicosapentaenoic Acid; Fatty Acids, Essential; Female; gamma-Linolenic Acid; Linoleic Acid; Linoleic Acids; Necrosis; Radiation Injuries, Experimental; Skin; Strontium; Swine; Yttrium Radioisotopes

Four different oils : onager oil, mixture of onager oil (20 p. cent) and middle class triglyceride, sunflower oil and soybean oil were given to the rat during three different periods of time : 1) during 3 months after weaning ; 2) during 6 months after weaning ; 3) from the 9th to 15th months. Three types of myocardial lesions were found : interstitial inflammatory reaction, foci of cellular necrosis and fibrosis. The semi-quantitative study of these lesions did not find important differences from one oil to the other, as well as with the controls. However, subgroups onager are among the least altered, particularly as far as necrotic lesions are concerned. Morphometry of mitochondria, despite evident alterations under electron microscope, gave similar results in every groups.

Topics: Animals; Cardiomyopathies; gamma-Linolenic Acid; Glycine max; Heart; Helianthus; Linolenic Acids; Microscopy, Electron; Myocarditis; Myocardium; Necrosis; Oils; Rats; Rats, Inbred Strains