Gould E, Woolley C S, McEwen B S
Laboratory of Neuroendocrinology, Rockefeller University, New York, New York 10021.
J Comp Neurol. 1991 Feb 15;304(3):408-18. doi: 10.1002/cne.903040306.
The rat dentate gyrus is a unique brain structure in that most of its neurons are born postnatally. Cell death is known to be an important phenomenon in brain development and yet it is at present unknown whether the dentate gyrus undergoes a period of naturally occurring cell death. In order to determine whether or not cell death plays a role in the development of the dentate gyrus, we examined the density of degenerating cells and healthy cells in the suprapyramidal and infrapyramidal granule cell blades and the hilus during the postnatal period. Light microscopic examination of Nissl-stained brain tissue revealed substantial numbers of pyknotic cells throughout the dentate gyrus during the first postnatal week. Quantitative analysis of the suprapyramidal blade showed a peak in the density of pyknotic cells at the end of the first postnatal week. This peak in the density of degenerating cells coincided with a significant decrease in the density of healthy cells in this region. No rostrocaudal gradient in cell death was observed for the suprapyramidal blade. However, cell death in the suprapyramidal blade proceeded along superficial to deep as well as lateral to medial gradients. Within the infrapyramidal blade/hilus, cell death occurred at different times depending on the rostrocaudal level of the dentate gyrus. Peak density of pyknotic cells was observed the day after birth in the rostral part of the infrapyramidal blade/hilus while pyknosis did not reach a peak in the middle and temporal thirds of this region until the end of the first postnatal week. Cell death in the infrapyramidal blade proceeded in a superficial to deep and lateral to medial direction. These results indicate that the dentate gyrus undergoes a significant period of naturally occurring cell death during the early postnatal period.
大鼠齿状回是一种独特的脑结构，因为其大多数神经元在出生后才产生。细胞死亡是脑发育中的一个重要现象，但目前尚不清楚齿状回是否经历自然发生的细胞死亡阶段。为了确定细胞死亡是否在齿状回的发育中起作用，我们在出生后的时期检查了上锥体和下锥体颗粒细胞层以及齿状回门中退化细胞和健康细胞的密度。对尼氏染色的脑组织进行光镜检查发现，在出生后的第一周，整个齿状回中有大量固缩细胞。对上锥体层的定量分析显示，在出生后第一周结束时，固缩细胞密度达到峰值。退化细胞密度的这个峰值与该区域健康细胞密度的显著下降相吻合。在上锥体层未观察到细胞死亡的前后梯度。然而，上锥体层的细胞死亡沿着从浅到深以及从外侧到内侧的梯度进行。在锥体下层/齿状回门内，细胞死亡根据齿状回的前后水平在不同时间发生。在锥体下层/齿状回门的前部，出生后第二天观察到固缩细胞的峰值密度，而在该区域的中部和颞部直到出生后第一周结束时，固缩才达到峰值。锥体下层的细胞死亡沿着从浅到深以及从外侧到内侧的方向进行。这些结果表明，齿状回在出生后早期经历了一段自然发生的显著细胞死亡时期。
