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The developing CNS, and in particular the visual system, is very sensitive to the effects of alcohol. Alcohol causes lipid peroxidation. Squalene, the major olive oil hydrocarbon, is a quencher of singlet oxygen and prevents the corresponding lipid peroxidation. We presumed that squalene can protect against the alcohol-induced damage already observed during the development of the chick retina. Alcohol+squalene was administered directly into the yolk sac of the egg of White Leghorn chicks at day 6 of incubation. The lipid composition of the retina was analyzed in embryos at E7, E11, E15 and E18. The proportions of phospholipids, free and esterified cholesterol, diacylglycerides and free fatty acids were estimated using the Iatroscan TLC/FID procedure. Gas chromatography and mass spectrometry were used to determine the fatty acid composition. The morphological study was carried out at E11 using semithin sections, and by means of immunohistochemical techniques at E19. Comparing the results obtained in control embryos, the administration of alcohol+squalene reduces the effects of alcohol on the total lipid composition of the retina during development. The effects were, in fact, of less magnitude than in embryos treated only with alcohol. The major phospholipid species of alcohol+squalene-treated embryos exhibited total recuperation at E15. As far as fatty acids are concerned, no significant changes were observed with regard to control embryos during development. From a morphological point of view, the retinas of alcohol+squalene-treated embryos show at E11 fewer cellular alterations than the retinas of alcohol-treated embryos. In this respect, the retinas of alcohol+squalene-treated embryos exhibited: a columnar cell arrangement similar to that observed in control retinas; few pycnotic cells and very few alterations in ganglion cell layers and in the optic nerve fibers layer. At E19 the recuperation of the expression of myelin oligodendrocyte specific protein (MOSP) in alcohol+squalene-treated embryos was recorded. Since squalene reduces the deleterious effects caused by alcohol on the lipid composition and the structure of the retina, squalene could act as a naturally occurring agent for the prevention of damage caused by abusive alcohol ingestion during pregnancy.

Background: Alcohol exposure causes alterations in the lipid content of different organs and a reduction of long-chain fatty acids. During embryo development, the central nervous system is extremely vulnerable to the teratogenic effects of alcohol, and the visual system is particularly sensitive., Methods: White Leghorn chick embryos were injected with 10- and 20-microl alcohol doses into the yolk sac at day 6 of incubation. The lipid composition of the retina was analyzed in embryos at day 7 of incubation (E7), E11, E15, and E18. The percentages of phospholipids, free cholesterol, esterified cholesterol, diacylglycerides, and free fatty acids were estimated by using an Iatroscan thin layer chromatography flame ionization detector. Gas chromatography and mass spectrometry were used to determine fatty acid composition. The morphological study was performed at E7, E11, and E19 by means of semithin and immunohistochemical techniques., Results: In the retina, alcohol causes the total lipid content to change, with a remarkable increase in free cholesterol and a dramatic decrease in esterified cholesterol. Diacylglycerides and free fatty acids tend to increase. Phosphatidylcholine and phosphatidylethanolamine decrease, whereas phosphatidylserine, sphingomyelin, and phosphatidylinositol increase. The main fatty acids of the retina also undergo changes. At E7, myriotic acid increases, and oleic acid and polyunsaturated fatty acids such as arachidonic acid and docosahexaenoic acid decrease. From E18 onward, there is some recovery, except for fatty acids, which recover earlier. From a morphological point of view, alcohol effects on retinal development are various: increase of intercellular spaces in all cell layers, pyknosis with loss of cellularity in the inner nuclear cell layer and ganglion cell layer, retarded or disorderly cell migration, early cell differentiation, and loss of immunoreactivity for myelin oligodendrocyte-specific protein., Conclusions: Acute alcohol exposure during embryo development causes the lipid composition of the retina to change, with a trend to recovery in the last stages. These alterations are in line with the changes observed at a morphological level.