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The ocular administration of nerve growth factor (NGF)
as eye drops (oNGF) has been shown to exert
protective effects in forebrain-injured animal
models, including adult diabetes induced by a single
injection of streptozotocin (STZ) (60 mg/kg body
weight). This type 1 diabetes model was used in this
study to investigate whether oNGF might extend its
actions on neuronal precursors localised in the
subventricular zone (SVZ). NGF or saline was
administrated as eye drops twice daily for 2 weeks
in rats with STZ-induced diabetes and healthy
control rats. The expression of mature and precursor
NGF and the NGF receptors, tropomyosin-related
kinase A and neurotrophin receptor p75, and the
levels of DNA fragmentation were analysed by ELISA
and western blotting.
Incorporation of bromodeoxyuridine was used to trace
newly formed cells. Nestin, polysialylated neuronal
cell adhesion molecule (PSA-NCAM), doublecortin (DCX)
and glial fibrillary acidic protein antibodies were
used to identify the SVZ cells by confocal
microscopy.
It was found that oNGF counteracts the STZ-induced
cell death and the alteration of mature/pro-NGF
expression in the SVZ. It also affects the survival
and differentiation of SVZ progenitors. In
particular, oNGF counteracts the reduction in the
number of cells expressing PSA-NCAM/DCX (neuroblast
type A cells) and the related reductions in the
number and distribution of nestin/DCX-positive cells
(C-type cells), or glia-committed cells (type B
cells), observed in the SVZ of diabetic rats.
These findings show that oNGF treatment counteracts
the effect of type 1 diabetes on neuronal precursors
in the SVZ, and further support the neuroprotective
and reparative role of oNGF in the brain.
For more information
European Journal of Neuroscience, Ocular nerve
growth factor administration counteracts the
impairment of neural precursor cell viability and
differentiation in the brain subventricular area of
rats with streptozotocin-induced diabetes, 2015;
10.1111/ejn.12854;
doi/10.1111/ejn.12854/abstract.
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