Maternal N-3 Long Chain Polyunsaturated Fatty Acids Increase N-3 Fatty Acids in Brain Glial Cells and Retina in the Rat and Improve Rod Sensitivity

Abstract

Purpose:: To evaluate the efficacy of long chain n-3 polyunsaturated fatty acids (LC-PUFA) given to female rats during gestation and lactation on the incorporation of n-3 PUFA in the retina and brain glial cells of the newborn rat, and to evaluate the consequences on the electroretinographic (ERG) response.

Methods:: Sprague Dawley rats were fed during gestation and lactation with a 20%-lipid rich diet containing 0.75% of EPA and 0.55% of DHA. The fatty acid profile was analyzed in the eyeball and in brain glial cells of the litters sacrificed at birth. The retina and brain glial cell phospholipids were similarly analyzed in 14 day-old rats and in the mothers. Standard scotopic and 10Hz flicker ERG were recorded in the mothers and weaning rats.

Results:: Dietary n-3 LC-PUFA did not modify any characteristics of the newborn rats (number of pups, mortality within the first days of life, weight or growth). Dietary n-3 LC-PUFA significantly lowered n-6 LC-PUFA and increased EPA and C22:5n-3 in brain glial cells and eyes of the newborn rats. A significant rise in DHA was observed in the eyes at birth (+30%) and in the retina of the mothers sacrificed after the lactating period (+20%). A similar DHA increase was observed in the retina at day 14, although at a lower level of magnitude. DHA was increased by 15 and 20% in brain glial cell phosphatidylserine (PS) and phosphatidylethanolamine (PE) of 14 day-old rats whereas no effect was observed in total phospholipids of brain glial cells. Conversely, n-6 LC-PUFA were lowered by 10 to 60% in the retina at day 14, and in brain glial cell PE and PS of the mothers sacrificed after weanling of the pups. Interestingly, as judged from the 10Hz flicker ERG data, n-3 LC-PUFA slightly improve rod sensitivity to light by 0.3 log unit.

Conclusions:: Gestation and lactation is a critical period for n-3 LC-PUFA accretion in the retina and brain, and for improving retinal function. Like in the brain, glial cells may be key contributors for the metabolism of fatty acids in the retina and might be targeted for n-3 LC-PUFA incorporation.

Keywords: lipids • development • electroretinography: non-clinical