Studies on Peripheral Nerve Regeneration: Microdispensing, Neurite Guidance and Galectins

The present thesis describes development of a microdispenser-based technique to create of protein patterns for neurite guidance. The same technique was also developed to allow direct positioning of dissociated cells, including neurons, on cell culture substrates. Finally the role of galectin-3 and 8 during nerve regeneration was investigated. The thesis consists of four papers (I-IV).

Microdispensing is a method similar to inkjet printing, which can be used for precise patterning of small volumes of liquids on substrates. The method proved to be a rapid and accurate instrument for the creation of protein patterns on cell culture substrates. Patterns made of bovine serum albumin were avoided by regenerating neurites from dorsal root ganglia, which instead preferred to grow on microdispensed laminin (I). Microdispensing could also be used to position cell directly on culture substrates without harming the cells. The technique was used for the construction of 2D miniature organs, i.e. a 2D dorsal root ganglion (II).

Galectin-3 and 8 (belonging to a family of animal lectins) were shown to inhibit neurite outgrowth in extracellular matrix substitute (ECM gel) but had no effects on neurite guidance when microdispensed on plastic surfaces (III). In addition, galectin-3 was shown to inhibit the proliferation of Schwann cells in cultured sciatic nerve segments, an effect independent of its lectin properties (IV).