In vitro comparison of motor and sensory neuron outgrowth in a 3D collagen matrix

In this work we set up an in vitro model, based on organotypic cultures of spinal cord slices and dorsal root ganglia explants from P7 rats, embedded in a collagen matrix and cultured under the same conditions. As specific reinnervation of end-organs is still an unresolved issue in peripheral nerve research, we characterized a model that allows us to compare under the same conditions motor and sensory neuron regeneration. RT97 labeling was used to visualize the regenerating neurites that extended in the collagen gel from both motor neurons in the spinal cord slices and sensory neurons in the DRG explants after a few days in vitro. By adding different neurotrophic factors in the collagen matrix, we evaluated the reliability of DRG and spinal cord preparations. Moreover, we also set up a co-culture with dissociated Schwann cells to further mimic the permissive environment of the peripheral nerve. Thus, these in vitro models can be useful tools to investigate mechanisms for the selective regeneration of sensory and motor neurons, which can be translated into in vivo models.