![](bg6.png)
substrate slopes, but it was reasonable to assume that
the guidance relied on extra-cellular cues, which
triggered some reorganization mechanisms in the
cytoskeleton. The actin cytoskeleton in cells
(fibroblasts, endothelia, and macrophages) reacting
to topography is organized in a way which we
believe to be appropriate for movement. Some
proteins, like semaphorines and ephrins, can inhibit
axons to grow the wrong way while other proteins
can attract axons to grow on the right way (Cook,
Tannahill et al. 1998). Compared with flat surface,
growth cones of the growing neurites on the slope
would get larger mechanical stress which can affect
the strength of the integrin–cytoskeleton links and
the integrin receptor distribution and conformation,
thus activating intracellular pathways active in cell
development and behaviour.
In future, we aim to make more experiments to
study the mechanism of slope modulation. For
example, we will put DRG explants on different
slope substrates to measure the growth rate of
neurites and observe the cytoskeleton morphology.
Even we will use quantitative real-time polymerase
chain reaction (qRT-PCR) to measure the magnitude
of changes in the expression of gene compliment
which regulates the neuron cell growth on different
topologies of substrates. Moreover, neurons are
usually not very likely to be the first cells to
encounter an implant as any topography may be
covered and obscured by glia cells (Franze 2013).
Therefore, we also need to study how slope affect
the glial cells.
ACKNOWLEDGEMENTS
This study was supported by the Natural Science
Foundation of China (grant number 61233015), the
National Basic Research Program of China (973
Program) (grant number SQ2012CB037202) and in
part by independent innovation fund of Huazhong
University of Science and Technology, Wuhan, P. R.
China (grant number 2013YGYL004). The authors
would like to thank Dr. Jun Ma and Dr. Jianfeng Xu
for their instruction in the experiments.
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