Sensory neuron number in neonatal and adult rats estimated by means of stereologic and profile‐based methods
Sensory neuron number in neonatal and adult rats estimated by means of stereologic and profile‐based methods
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DOI：
10.1002/(sici)1096-9861(19970915)386:1
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发表时间：
1997-09
影响因子：
2.5
通讯作者：
Gregory J. Popken;P. Farel
中科院分区：
文献类型：
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作者：
Gregory J. Popken;P. Farel
出生后神经元的增加，如果发生的话，将对发育过程的概念化和对替换因损伤或疾病而失去的神经元的努力产生深远的影响。尽管背根神经节（DRGs）具有边界清晰和功能同质性的优势，但比较不同年龄或大小动物的DRGs神经元数量的研究得出了相互矛盾的结果。在本研究中，比较了新生雄性大鼠（约11日龄，平均体重24.5 g，平均体积25 cm3）和成年雄性大鼠（约80日龄，平均体重373.5 g，平均体积346 cm3） DRGs L3-L6神经元数量。神经元数量的估计是通过使用体视学（物理方向）和剖面计数（细胞核内的一个或多个核仁）方法得出的。通过将神经元数量估计值与神经元子集的三维重建结果进行比较，评估了这两种方法的可靠性和有效性。研究发现，使用物理检测器的推荐方案可以准确估计神经元数量，但神经节中神经元的异质性分布导致采样误差高达50%。通过增加检查的指示器对的数量，提高了可靠性。核/核仁谱的计数更可靠，但引入了一种偏差，这种偏差与实验假设相反，即新生儿神经元数量的估计值超过了实际值。尽管如此，两种方法都表明成年大鼠比新生儿有更多的DRG神经元。成人的特征计数高出19% （P < 0.01，双尾t检验）；物理检测器数据显示，成年大鼠的神经元数量比新生大鼠多28% （P < 0.05）。成人和新生儿之间神经元数量的差异可能是由于神经元增殖或神经元分化较晚，直到成年才呈现典型的外观。[j]中华神经科杂志，2006。©1997 Wiley‐Liss, Inc。
Postnatal neuron addition, if it occurred, would have profound implications both for the conceptualization of developmental processes and for efforts directed at replacing neurons that were lost to injury or disease. Although dorsal root ganglia (DRGs) offer the advantages of clear boundaries and functional homogeneity, studies comparing neuron number in the DRGs of animals of different ages or sizes have yielded conflicting results. In the present study, neuron number in DRGs L3–L6 was compared in neonatal (approximately 11 days old, mean weight of 24.5 g, mean volume of 25 cm3) and adult (approximately 80 days old, mean weight of 373.5 g, mean volume of 346 cm3) male Sprague‐Dawley rats. Estimates of neuron number were derived by using both stereological (physical disector) and profile‐counting (one or more nucleoli within a nucleus) methods. The reliability and validity of the two methods were evaluated by comparing estimates of neuron number with those derived from three‐dimensional reconstruction of a subset of neurons. The recommended protocol for using the physical disector was found to give accurate estimates of neuron number, but the heterogeneous distribution of neurons in the ganglion led to sampling errors of up to 50%. Reliability was improved by increasing the number of disector pairs examined. Counts of nuclear/nucleolar profiles were more reliable, but introduced a bias that worked against the experimental hypothesis in that estimates of neuron number in neonates exceeded actual values. Nonetheless, both methods indicated that adult rats had more DRG neurons than did neonates. Profile counts were 19% higher in adults (P < .01, two‐tailed t‐test); and data obtained by using the physical disector showed that adult rats had 28% more neurons than did neonates (P < .05). The difference in neuron number between adults and neonates could be due either to neuron proliferation or to late differentiation of neurons that do not assume a typical appearance until adulthood. J. Comp. Neurol. 386:8–15, 1997. © 1997 Wiley‐Liss, Inc.