REGENERATING TISSUES FROM THE COCKROACH, LEUCOPHAEA MADERAE: NERVE REGENERATION IN VITRO

¹ Metabolism and Radiation Research Laboratory, Entomology Research Division, Agricultural Research Service, United States Department of Agriculture, Fargo, North Dakota 58102

1. The regeneration of nerve tissues which occurs in vitro is comparable, within limits, to that which occurs in vivo. Both sensory and motor nerve elements take part in the regenerative process. Blood and glial cells play an important role in forming the cell bridge that facilitates the migration of the nerve axons.

2. The presence of ganglion tissue in the growth chamber exerts a demonstrable stimulating influence on the outgrowth of cells from the nerve stump of the leg regenerate. However, the presence of the leg regenerate appears to have no effect on the outgrowth of cells from the ganglion.

3. A tactile or thigmotropic type of behavior by the migrating axons is evident that explains several of the phenomena described.

4. With such similarity between the development in vivo and in vitro, the advantages of the in vitro technique become apparent. High-resolution photography of the activities of single cells is possible, and the activity can be followed for many days by using time-lapse cinephotomicrography. Also, great experimental flexibility is possible because there need he no interference from other tissues. In addition, tissues from several insects may be included in a single chamber which may make it possible to investigate a number of phenomena that are not otherwise accessible for experimentation.