Molecular Biosciences Graduate Program, Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, 604 Allison Road, Piscataway, NJ 08854-8082, USA.
J Biosci Bioeng. 2010 Oct;110(4):459-70. doi: 10.1016/j.jbiosc.2010.04.004. Epub 2010 May 10.
Previous studies have shown that dendrites are influenced by substrate stiffness when neurons are plated in either pure or mixed cultures. However, because substrate rigidity can also affect other aspects of culture development known to impact dendrite branching, such as overall cell number, it is unclear whether substrate stiffness exerts a direct or indirect effect on dendrite morphology. In this study, we determine whether substrate stiffness plays a critical role in regulating dendrite branching independent of cell number. We plated primary mixed hippocampal cultures on soft and stiff gels, with Young's moduli of 1 kPa and 7 kPa, respectively. We found that neurons plated on stiffer substrates showed increased branching relative to neurons grown on softer substrates at the same cell number. On the stiff gels, we also observed a cell number-dependent effect, in which increasing initial plating density decreased dendrite branching. This change correlates with an increase in extracellular glutamate. We concluded that both cell number and substrate stiffness play roles in determining dendrite branching, and that the two effects are independent of one another.
先前的研究表明，当神经元在纯培养或混合培养中接种时，树突会受到基质硬度的影响。然而，由于基质刚性也会影响到其他已知会影响树突分支的培养发展方面，例如总细胞数，因此不清楚基质硬度是否对树突形态有直接或间接的影响。在这项研究中，我们确定了基质硬度是否在独立于细胞数的情况下对调节树突分支起着关键作用。我们将原代混合海马培养物接种在杨氏模量分别为 1 kPa 和 7 kPa 的软凝胶和硬凝胶上。我们发现，与在较软基质上生长的神经元相比，在较硬基质上接种的神经元在相同的细胞数下表现出更多的分支。在硬凝胶上，我们还观察到了一种依赖于细胞数的效应，即增加初始接种密度会减少树突分支。这种变化与细胞外谷氨酸的增加有关。我们得出的结论是，细胞数和基质硬度都在决定树突分支方面发挥作用，并且这两种效应是相互独立的。
