The high-dose fish oil supplementation increased Mfsd2a expression without altering DHA levels in the retina of healthy mice

Abstract

• The healthy retina requires daily omega-3 PUFA supplementation. • High-dose FO supplementation can be more beneficial than currently recommended doses. • High-dose FO supplementation alters lipid content in the eye. • High-dose FO supplementation has the potential to fortify retinal blood vessels. The recommended fish oil (FO) supplementation doses often yield low omega-3 polyunsaturated fatty acids (PUFAs) tissue bioavailability, and higher doses (up to 10 g per day) have been increasingly recommended. However, the exact effects of such FO supplementation on the healthy retina and retinal pigmented epithelium (RPE) are unknown. Our study showed that the high dose FO treatment did not imbalance the rigorous docosahexaenoic acid (DHA, C22:6n3) homeostasis in the retina and RPE in the three-month-old female B6/SLJ mice. Instead, we have found the significant increase in the expression of Mfsd2a, the main DHA transporter. Mfsd2a is also an essential regulator of blood vessel transcytosis and the decrease in Mfsd2a expression can be a risk factor for developing leaky blood vessels. Therefore, the high-dose FO supplementation emerges as the prophylactic fortifier of the retinal blood vessels.