Park Eek Joong, Suh Miyoung, Clandinin M Thomas
Alberta Institute for Human Nutrition, University of Alberta, Edmonton, Canada.
Invest Ophthalmol Vis Sci. 2005 Jul;46(7):2571-5. doi: 10.1167/iovs.04-1439.
During early development, the ganglioside composition of the retina changes significantly, in that GD3 becomes the primary ganglioside in the mammalian retina. Because gangliosides play an important role in neuronal cell differentiation and proliferation, this change in ganglioside profile may indicate retinal maturation. Dietary long-chain polyunsaturated fatty acids (LCPs) such as 20:4n-6 and 22:6n-3 improve visual acuity in infants. Dietary LCPs stimulate neonatal retinal development by altering membrane phospholipids, which in turn affect cell signaling pathways. It is unknown whether dietary ganglioside and LCPs affect the metabolism of phospholipids and gangliosides during retinal development.
Male Sprague-Dawley rats (18 days old) were fed semipurified diets consisting of 20% fat (control diet) for 2 weeks containing either 0.1% ganglioside enriched in GD3 (GG diet) or 1% 20:4n-6 and 0.5% 22:6n-3 (LCP diet) in the control diet. The profile of ganglioside and phospholipid was measured.
The GG diet increased the ganglioside content by 39% in the retina, with a relative increase in GD3 (by 13%). Dietary LCPs significantly increased the relative levels of GD3 (by 19%, P < 0.01). Total phospholipid was decreased by the LCP-supplemented diet (by 28%). Phosphatidylcholine and phosphatidylserine increased with concomitant decreases in phosphatidylinositol and lyso-phosphatidylethanolamine when animals were fed either the LCP or the GG diet.
Animals fed dietary ganglioside increased in total retinal ganglioside and GD3 content during retinal development, with a concomitant alteration of phospholipid metabolism. Feeding animals dietary LCPs also affected ganglioside metabolism in the developing retina, suggesting a new mechanism by which these dietary lipids may promote maturation of photoreceptor cells.
在早期发育过程中,视网膜的神经节苷脂组成会发生显著变化,即GD3成为哺乳动物视网膜中的主要神经节苷脂。由于神经节苷脂在神经元细胞分化和增殖中起重要作用,这种神经节苷脂谱的变化可能表明视网膜成熟。膳食中的长链多不饱和脂肪酸(LCPs),如20:4n-6和22:6n-3,可提高婴儿的视力。膳食LCPs通过改变膜磷脂来刺激新生儿视网膜发育,进而影响细胞信号通路。目前尚不清楚膳食神经节苷脂和LCPs在视网膜发育过程中是否会影响磷脂和神经节苷脂的代谢。
给18日龄的雄性Sprague-Dawley大鼠喂食半纯化日粮,其中脂肪含量为20%(对照日粮),持续2周,对照日粮中要么含有0.1%富含GD3的神经节苷脂(GG日粮),要么含有1%的20:4n-6和0.5%的22:6n-3(LCP日粮)。测量神经节苷脂和磷脂的谱图。
GG日粮使视网膜中的神经节苷脂含量增加了39%,GD3相对增加(增加了13%)。膳食LCPs显著增加了GD3的相对水平(增加了19%,P<0.01)。补充LCP的日粮使总磷脂减少(减少了28%)。当给动物喂食LCP或GG日粮时,磷脂酰胆碱和磷脂酰丝氨酸增加,同时磷脂酰肌醇和溶血磷脂酰乙醇胺减少。
在视网膜发育过程中,喂食膳食神经节苷脂的动物视网膜总神经节苷脂和GD3含量增加,同时磷脂代谢发生改变。给动物喂食膳食LCPs也会影响发育中视网膜的神经节苷脂代谢,提示这些膳食脂质促进光感受器细胞成熟的新机制。