Karlsen A S, Korbo S, Uylings H B M, Pakkenberg B
Research Laboratory for Stereology and Neuroscience, Bispebjerg and Frederiksberg Hospitals, Bispebjerg Bakke 23, 11B 2, DK-2400 Copenhagen NV, Denmark.
Department of Anatomy and Neurosciences, VU University Medical Center, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands.
Neuroscience. 2014 Oct 24;279:253-9. doi: 10.1016/j.neuroscience.2014.08.046. Epub 2014 Sep 8.
The total number of neurons and glial cells in the mediodorsal thalamic (MDT) nucleus of four aged females with Down syndrome (DS; mean age 69years) was estimated and compared to six age- and sex-matched controls. The MDT nucleus was delineated on coronal sections, and cell numbers (large and small neurons, oligodendrocytes, and astrocytes) were estimated using the optical fractionator technique. The DS brains had an average of 3.41×10(6) total neurons in the MDT nucleus in contrast to 5.97×10(6) in the controls, with no overlap (2p=0.004), affecting large (projecting) and small (local inhibitory) neurons nearly equally. In contrast, we observed no significant differences in either glial cell population. The cortical structures of the same four DS brains were previously estimated to be half the normal size of controls with a reduction in cell numbers whereas the basal ganglia were unaffected. As DS brains are affected by developmental delay, premature aging, and Alzheimer-like pathology, the finite cause of the reduced number of cells in MDT nucleus cannot be determined; however, these findings provide stereological evidence for a local reduction in neuron numbers in the MDT nucleus, which could affect the cognitive capacity of patients with DS.
对四名患有唐氏综合征（DS；平均年龄69岁）的老年女性的丘脑背内侧核（MDT）中的神经元和神经胶质细胞总数进行了估计，并与六名年龄和性别匹配的对照者进行了比较。在冠状切片上勾勒出MDT核，并使用光学分选技术估计细胞数量（大神经元和小神经元、少突胶质细胞和星形胶质细胞）。DS组大脑的MDT核中平均有3.41×10⁶个神经元，而对照组为5.97×10⁶个，两者无重叠（P=0.004），对大（投射）神经元和小（局部抑制）神经元的影响几乎相同。相比之下，我们观察到两组神经胶质细胞数量均无显著差异。之前估计，这四名DS患者大脑的皮质结构大小仅为对照组的一半，细胞数量减少，而基底神经节未受影响。由于DS患者大脑受发育迟缓、早衰和阿尔茨海默样病理影响，MDT核中细胞数量减少的确切原因尚无法确定；然而，这些发现提供了体视学证据，表明MDT核中神经元数量局部减少，这可能会影响DS患者的认知能力。
