Annual Report 2007 - The Australian Nanotechnology Network

It was expected that release of both neurotrophins would enhance nerve survival and growth
significantly compared to release of either neurotrophin alone, as the action of the nerve growth
factors is synergistic. Figure 3 shows that the experimental data confirmed expectations, with a
large increase seen with both neurotrophins released from PPy/pTS films.
No neurites per explant
120
100
80
60
40
20
0
unstim
stim
PPy/pTS PPy/pTS/NT-3 PPy/pTS/NT-3/BDNF
Figure 3 – Auditory nerve explant survival is greatly enhanced with release of both BDNF and NT-3 from
PPy/pTS by electrical stimulation
The final piece of work has not yet been fully analysed – the implantation of PPy/pTS/NT-3 I125
to trace release of NT-3 in a guinea pig cochlea, and look at effects of released NT-3 on auditory
nerve survival. The animal experimental period was 4-5 weeks, and 2 weeks of subsequent
processing was required to prepare the tissues for application of a radiation-sensitive coating,
which remains on the tissue for 1-3 months. As such, several groups of data have not yet been
analysed for radioactive tracing of NT-3, and results will not be presented. However, the analysis
of nerve regeneration has been completed, and the results are shown in Figure 4. The average
number of nerves was higher in the left cochlear (which had been implanted with PPy/NT-3 –
“125I stim L”) than any other cochlear observed (including untreated right cochleas, and
implanted, unstimulated left cochleas “125I NT3 L”).
Dr. Rachael Richardson trained me in During my time at RVEEH, I assisted in
many dissection, cell culture and microscopy several animal procedures.
techniques.
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