Studying the growth of nerve cells is a difficult proposition because one has to isolate them from surrounding tissue and then analyze the very fine slices under the microscope. This process can be time consuming and prone to mistakes and errors.
An international team of researchers headed by neurobiologists at Max-Planck-Institut für Neurobiologie have developed a method of making the spinal cord transparent so that slicing and their 3D reconstruction is not necessary.
Details from the announcement:
Spinal cord tissue is opaque due to the fact that the water and the proteins contained in it refract light differently. Thus, the scientists removed the water from a piece of tissue and replaced it by an emulsion that refracts light in exactly the same way as the proteins. This left them with a completely transparent piece of tissue. “It’s the same effect as if you were to spread honey onto textured glass”, Ali Ertürk, the study’s first author adds. The opaque pane becomes crystal clear as soon as the honey has compensated for the surface irregularities. The new method is a leap forward in regeneration research. By using fluorescent dyes to stain individual nerve cells, scientists can now trace their path from all angels in an otherwise transparent spinal cord section. This enables them to ascertain once and for all whether or not these nerve cells recommenced their growth following injury to the spine – an essential prerequisite for future research.