Our results do not support our hypothesis. Interestingly, both of our additives, DEET , an oxidant, and Gingko biloba , an antioxidant, resulted in more neurite growth than our control subject pool, which could possible mean that oxidative influences do not have a strong affect on neuron growth. . More so , DEET, an oxidative stress and a potentially toxic substance, had the most neuron growth. These results indicate that perhaps DEET does increase more neurite growth than Gingko biloba, a health supplement. DEET and Ginkgo biloba exhibit antagonistic properties of oxidation and antioxidation and yet both led to a stimulatory response, which could mean that perhaps these properties do not play a significantly role in neurite growth. This could also mean that the oxidative influences of DEET are stimulatory. Overall what we do know is that DEET does stimulate neuron growth, at least under the perimeters of this experiment. However, because both additives are made of many different chemicals, there could be many different unknown stimulating/inhibiting factors, which is why more research is needed on this subject.
We believe that some reasons other, more methodological reasons for for these results could be: 1. Gingko cultures accumulated bacteria from various unknown sources, possibly diminishing/aiding neurite growth in cultures, 2. Possible contaminants entering culture dishes during an allotted waiting period of 48 hours could have altered growth, 3. DEET sample size is much smaller than the Gingko sample size. Our data was compiled over a two-week span, and our sample sizes ranged from n=79 for DEET to n=158 for Gingko.
Figure 1. Neurite growth as a function of cell culture additive
If we had had more time for this experiment we would have liked to examine the effects of treating neurons previosuly exposed to the DEET compound, and therefore already oxidatively stressed, with the Ginkgo Biloba extract. Further research could be done on not only the enhancement properties, but also the repairative properties of Ginkgo Biloba Extract. We also would have liked to examined a larger sample size of cells treated with DEET, as this was our lowest smple sample size. We also encountered some problem with bacterial infections, most likely stemming from an infected culture medium or trypsin solution. We still got results despite the bacteria growth in some of our cultures, but with more time we would have eliminated the infections and hopefully examined more cell growth.
Deet DEET technical fact sheet from the National Pesticide Information Center