Neuroscience Graduate Program, Wake Forest School of Medicine, Winston-Salem, North Carolina.
Biol Psychiatry. 2013 Dec 15;74(12):890-7. doi: 10.1016/j.biopsych.2013.03.013. Epub 2013 Apr 19.
The anterior hippocampus is associated with emotional functioning and hippocampal volume is reduced in depression. More women are clinically depressed than men, yet the depressed female brain is little studied. We reported reduced anterior hippocampal volume in behaviorally depressed adult female cynomolgus macaques; the mechanisms contributing to that reduction are unknown. The present study represents the first systematic morphological investigation of the entire hippocampus in depressed female primates.
Cellular determinants of hippocampal size were examined in subregions of anterior and posterior hippocampus in antidepressant-naïve, adult female monkeys characterized for behavioral depression and matched on variables that influence hippocampal size (n = 8 depressed, 8 nondepressed). Unbiased stereology was used to estimate neuronal and glial numbers, neuronal soma size, and regional and layer volumes.
Neuropil and cell layer volumes were reduced in cornu ammonis (CA)1 and dentate gyrus (DG) of the anterior but not the posterior hippocampus of depressed compared with nondepressed monkeys. Glial numbers were 30% lower in anterior CA1 and DG of depressed monkeys, with no differences observed in the posterior hippocampus. Granule neuron number tended toward a reduction in anterior DG; pyramidal neuron number was unchanged in any region. Size of pyramidal neurons and glial densities tended to be reduced throughout the whole hippocampus of depressed monkeys, whereas neuronal densities were unchanged.
The reduced size of the anterior hippocampus in depressed female monkeys appears to arise from alterations in numbers of glia and extent of neuropil, but not numbers of neurons, in CA1 and DG.
前海马体与情绪功能有关，而海马体体积在抑郁症中会减小。患有临床抑郁症的女性比男性多，但对女性抑郁大脑的研究甚少。我们曾报道过行为抑郁的成年雌性食蟹猴的前海马体体积减小；导致这种减小的机制尚不清楚。本研究代表了对抑郁雌性灵长类动物整个海马体进行的首次系统形态学研究。
在未经抗抑郁药物治疗、具有行为抑郁特征且受影响海马体大小的变量（n = 8 名抑郁，8 名非抑郁）相匹配的成年雌性猴子的前海马体和后海马体的亚区中，检查了海马体大小的细胞决定因素。使用无偏立体学来估计神经元和神经胶质数量、神经元体大小以及区域和层体积。
与非抑郁猴子相比，抑郁猴子的前海马体（CA1 和齿状回）的神经突和细胞层体积减小，但后海马体没有变化。前 CA1 和 DG 中的神经胶质数量减少了 30%，而在后海马体中没有差异。抑郁猴子的前齿状回颗粒神经元数量趋于减少；而任何区域的锥体神经元数量都没有变化。在整个海马体中，锥体神经元和神经胶质密度的大小都趋于减小，而神经元密度保持不变。
抑郁雌性猴子的前海马体体积减小似乎是由于 CA1 和 DG 中的神经胶质数量和神经突扩展的改变，而不是神经元数量的改变。
