Katz M L, White H A, Gao C L, Roth G S, Knapka J J, Ingram D K
Mason Institute of Ophthalmology, University of Missouri School of Medicine, Mason Institute of Ophthalmology, Columbia 65212.
Invest Ophthalmol Vis Sci. 1993 Nov;34(12):3297-302.
The accumulation of age pigment, or lipofuscin, in postmitotic cells appears to be a universal feature of the aging process in animals. In mammals, the lipofuscin content of the retinal pigment epithelium (RPE) increases progressively during senescence. Dietary restriction has been shown to slow the rate at which many biologic parameters change during aging. Experiments were conducted to determine if dietary restriction alters the rate of age pigment accumulation in the RPE.
Male Wistar rats were placed on one of three dietary regimens starting at weaning. One group was fed a nutritionally complete diet ad libitum. Another group was fed the same diet but was only allowed to consume 60% as much food daily as the ad libitum group ate. The final group was fed ad libitum a nutritionally complete diet that had a lower caloric density per gram than the diets fed to the other animals primarily because of the replacement of carbohydrate with oat fiber. Ultrastructural morphometric analysis was used to determine the RPE age pigment content in the first group at 6 months of age, and in all of the groups at 18 months of age.
Dietary restriction, achieved either by reducing total food intake or by reducing the caloric content of the diet, resulted in significant decreases in RPE lipofuscin accumulation.
Dietary restriction provides a relatively simple means by which RPE age pigment content can be modulated. This should prove useful in assessing the role of RPE lipofuscin accumulation in age-related retinal disorders. That the oat fiber diet fed ad libitum was almost as effective as restriction of total food intake in slowing RPE age pigment accumulation indicates that the effect of restricted caloric intake is not mediated by almost constant hunger.
有丝分裂后细胞中衰老色素即脂褐素的积累似乎是动物衰老过程的一个普遍特征。在哺乳动物中，视网膜色素上皮（RPE）的脂褐素含量在衰老过程中会逐渐增加。饮食限制已被证明可减缓衰老过程中许多生物学参数变化的速率。进行实验以确定饮食限制是否会改变RPE中衰老色素的积累速率。
雄性Wistar大鼠从断奶开始采用三种饮食方案之一。一组随意进食营养完全的饮食。另一组喂食相同的饮食，但每天仅允许摄入随意进食组食物量的60%。最后一组随意进食一种营养完全但每克热量密度低于其他动物所喂食饮食的饮食，这主要是因为用燕麦纤维替代了碳水化合物。使用超微结构形态计量分析来确定第一组6个月龄时以及所有组18个月龄时的RPE衰老色素含量。
通过减少总食物摄入量或降低饮食热量含量实现的饮食限制，导致RPE脂褐素积累显著减少。
饮食限制提供了一种相对简单的方法来调节RPE衰老色素含量。这在评估RPE脂褐素积累在年龄相关性视网膜疾病中的作用方面应会证明是有用的。随意喂食的燕麦纤维饮食在减缓RPE衰老色素积累方面几乎与限制总食物摄入量一样有效，这表明热量摄入受限的效果并非由几乎持续的饥饿介导。
