Díaz-Cintra S, Cintra L, Ortega A, Kemper T, Morgane P J
Departamento de Fisiologia, Ciudad Universitaria, México.
J Comp Neurol. 1990 Feb 1;292(1):117-26. doi: 10.1002/cne.902920108.
The effect of protein deprivation on rapid Golgi impregnated pyramidal neurons in layers II/III and V of the rat visual cortex was studied at 30, 90, and 220 days of age using morphometric methods. In order to mimic human under-nutrition female rats were adapted to either an 8% or control 25% casein diet 5 weeks prior to conception and maintained on these diets during gestation and lactation. The pups were then weaned and maintained on their respective diets. The undernourished rats showed a significant decrease in brain weight only at 90 days, indicating that the protein deprivation had a mild effect on brain development. Correspondingly, the number of significant histological differences between the two diet groups were least at 30 and 220 days of age. The effect of the diet was greater on layer V than on layer II/III pyramids. At 30 days of age the effect of the diet was different on the pyramids of these two cell layers, at 90 days there was a mixture of similar and dissimilar effects, and at 220 days the pyramids of these two cell layers showed only minor differences between the two diet groups. Analysis of age-related changes indicated that the effect of the diet was different on layer II/III pyramids compared to layer V pyramidal cells. These different effects apparently accounted for the progression from a dissimilar effect of the diet at 30 days on the pyramids of the two cell layers to only minor differences between them at 220 days. Further analysis of these age-related changes shows that two prominent effects of protein deprivation are for age-related changes to occur in undernourished rats but not in controls and for age-related changes to be out-of-phase with each other in the two diet groups. From these findings, and a review of similar studies in the literature, we propose that these mechanisms are a prominent effect of undernutrition in the post-weaning period and help account for the unexpected increases in morphometric measurements noted in undernourished rats in this and other studies.
采用形态测量学方法，研究了蛋白质缺乏对30日龄、90日龄和220日龄大鼠视觉皮层II/III层和V层中经快速高尔基浸染的锥体神经元的影响。为模拟人类营养不良的情况，在受孕前5周，将雌性大鼠分别适应8%或对照25%的酪蛋白饮食，并在妊娠和哺乳期维持这些饮食。然后将幼崽断奶，并维持各自的饮食。营养不良的大鼠仅在90日龄时脑重量显著下降，表明蛋白质缺乏对脑发育有轻微影响。相应地，两个饮食组之间显著的组织学差异数量在30日龄和220日龄时最少。饮食对V层的影响大于对II/III层锥体的影响。在30日龄时，饮食对这两个细胞层锥体的影响不同；在90日龄时，有相似和不同影响的混合情况；在220日龄时，这两个细胞层的锥体在两个饮食组之间仅显示出微小差异。对与年龄相关变化的分析表明，饮食对II/III层锥体的影响与对V层锥体细胞的影响不同。这些不同的影响显然解释了从30日龄时饮食对两个细胞层锥体的不同影响到220日龄时它们之间仅有微小差异的进展。对这些与年龄相关变化的进一步分析表明，蛋白质缺乏的两个显著影响是，营养不良的大鼠会出现与年龄相关的变化，而对照组则不会，并且两个饮食组中与年龄相关的变化彼此不同步。基于这些发现以及对文献中类似研究的综述，我们提出这些机制是断奶后营养不良的一个显著影响，并有助于解释在本研究和其他研究中营养不良大鼠形态测量值意外增加的原因。
