Retrograde transport of doxorubicin (adriamycin) in peripheral nerves of mice.

Doxorubicin (adriamycin) is a fluorescent compound which is widely used in the treatment of malignant tumors due to its capacity to bind and influence the DNA in the nucleus of cells. We have now observed that the compound after injection into a skeletal muscle of adult mice is transported to the corresponding nerve cell bodies, i.e. can be used as a retrograde tracer in neuroanatomical and neuropathological research. Six hours after injection into the tongue nerve cell nuclei were labeled in the hypoglossal nuclei of the brainstem. The fluorescent tracer had the same distribution as the chromatin. Glial nuclei in the vicinity of the hypoglossal neurons were also labeled presumably due to a transfer from the neurons to the glial cells during life or during the histochemical procedure. Since doxorubicin is also neurotoxic it might be a useful tool in neurobiological research, particularly if the labeled neurons later on will show toxic effects. In this way the compound could be used in models for experimental motor neuron disease and provide a means by which retrograde fluorescent tracing and a degeneration method can be combined for studies on various neuronal systems.