Schönheit B, Haensel P
Institut für Anatomie des Bereiches Medizin der Humboldt-Universität Berlin.
J Hirnforsch. 1988;29(6):599-615.
The experimental animals were 60 days old rats which had been suffering from undernutrition during day 1 till day 20 of their early postnatal life. The recovery from the retardation in brain development induced by the experiment was investigated by quantitative light microscopical methods in GOLGI impregnated material. In pyramidal neurons of lamina III or V of the anterior cingulate cortex several neuronal parameters were estimated in a single dendritic field (EDF) indicative for the development of the dendritic tree and spine distribution of these neurons. The results demonstrate a sufficient recovery in those cases when the rehabilitation is beginning already within the period of intensive brain growth. The duration of this growth spurt is prolongated in the experimental animals. Therefore, after the starvation period the brain is supposed to have some potency for further neuronal differentiation, also beyond the 20th day of life. This fact is considered to be decisive for a full recovery. After the starvation period at day 20 the lamina V pyramidal neurons were found to have developed a significantly smaller dendritic tree (minus 15%) equipped with a strongly reduced spine number (minus 30%). After the recovery time of 40 days the control values were reached, moreover, the spine density in apical dendrites was enhanced in comparison to controls. Likewise, in the lamina III pyramidal neurons of experimental animals, the apical dendritic tree was shortened by 25-30%, the basal dendritic tree by 10% at the end of the undernutrition period. However, after recovery of 40 days the dendritic tree of these neurons developed a significant overshoot of 15-20% in comparison to controls. The spine number at basal dendrites was similar to controls, but at apical dendrites significantly higher. The differences in the recovery pattern of both neuron types are explained by the hypothesis that the lamina III pyramidal neurons are phylogenetically younger and, therefore, have a considerably longer postnatal differentiation phase. Thus, they show a stronger retardation in growth by the undernutrition. However, during rehabilitation and recovery they show a larger increment in growth and differentiation.
实验动物为60日龄大鼠，它们在出生后早期（第1天至第20天）经历了营养不良。通过定量光学显微镜方法，在高尔基染色材料中研究了由实验诱导的大脑发育迟缓的恢复情况。在前扣带回皮质第III或V层的锥体细胞中，在单个树突场（EDF）中估计了几个神经元参数，这些参数可指示这些神经元的树突发育和棘分布。结果表明，在大脑快速生长期间开始康复的情况下，恢复情况良好。实验动物的这个生长突增期延长了。因此，饥饿期过后，大脑被认为具有进一步神经元分化的潜力，甚至在出生后第20天之后。这一事实被认为是完全恢复的决定性因素。在第20天饥饿期过后，发现第V层锥体细胞发育出明显更小的树突（减少15%），棘数量大幅减少（减少30%）。经过40天的恢复时间后，达到了对照值，此外，与对照组相比，顶树突中的棘密度增加。同样，在实验动物的第III层锥体细胞中，在营养不良期结束时，顶树突缩短了25 - 30%，基底树突缩短了10%。然而，经过40天的恢复后，这些神经元的树突与对照组相比显著过度生长了15 - 20%。基底树突的棘数量与对照组相似，但顶树突的棘数量明显更高。两种神经元类型恢复模式的差异可以用以下假说来解释：第III层锥体细胞在系统发育上更年轻，因此出生后分化阶段长得多。因此，它们因营养不良而生长迟缓更明显。然而，在康复和恢复过程中，它们的生长和分化增量更大。
