how can DRG (dorsal root ganglion) cultures be used in neuroscience cell biology and what can they measure?

Answer 1

DRG neurons are sensory nerve cells, meaning they convey sensory information from the periphery (skin, muscles, etc.) to the spinal cord and brain. They are called dorsal root ganglia because the cell bodies (containing the nucleus) are bundled togther in little "balls" lying outside of the spinal cord - ganglia. During development these neurons send out one major process or axon which split into two processes; one grow to your skin or muscle, or wherever in your body and the other process grows through the dorsal root and enters the spinal cord. This means that DRG neurons are located both in the peripheral nervous and central nervous systems and grow in both environments during development. Anyway, DRG neurons are very accessible and easy to harvest in embryonic, young, and adult animals and they survive well in culture. Typically, DRG neurons are cultured from rats, mice, and chicks. I haven't worked with chicks, but I have cultured more rat DRGs than I care to think about. In addition to being easy to obtain and keep alive, you can get a lot of neurons from one animal. Doing a full prep from an adult rat, you can get ~50-60 DRGs, and from those, ~120,000 neurons on average. I usually culture them on 12 mm coverslips and I use 2000 per cover slip. So, you can get a lot of cultures out of one rat.
My lab mainly looks at spinal cord injury and regeneration. We use DRG cultures as a screening tool for treatments that may increase growth of injured neurons following a spinal cord injury. You can compare their growth on different subrates, treat with neurotrophins, basically use any strategy you can come up with to increase their growth potential. Conversely, you can also try to make them grow less, to replicate and figure out what may be inhibiting their growth after an injury in vivo. DRG cultures are a nice model because you can minimize the number of animals used, and limit the complexity of the experiments. These cultures can be done relatively cheaply and are relatively quick (I allow my cultures to grow for five days). Then once you find a treatment with a promising effect, you can then translate the treatment to an animal model for more detailed in vivo analysis. Hope this helps, I could write much more, but I tried to give you a quick overview.

Answer 2

Most cells used in cell biology are cell lines - they are derived from self-replicating tumour cells. Their biology is therefore different from primary cells which are directly derived from NORMAL tissue.

DRG neurons are not particularly difficult to culture. The culture is merely a techique that allows the set up of cells that can then be used for various techniques. Examples would include electrophysiology on cell membrane channels, imaging of various cellular components such as mitochondria in vivo, they can be used for survival assays in toxicity tests, they can be used for immunocytochemistry or western blot experiments to quantitate expression of specific proteins in the cells, they can be used for RNA expression studies using microarrays. The possibilities are innumberable!

The limit really is only the imaginativeness and the resourcefulness of the scientist, and the limits of modern cell biology.