Nuclear Pore Changes and Absence of Apoptosis in Lumbar Dorsal Root Ganglion Neurons of Doxorubicin-Intoxicated Rats

Doxorubicin (DXR) produces degeneration of neurons in the lumbar dorsal root ganglion (DRG) in rats. Light microscopic studies, which included the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling method, and electron microscopic observation revealed that the moderate nuclear and remarkable cytoplasmic degeneration of DRG neurons of Sprague-Dawley rats after intravenous administration of 8 mg/kg of DXR was cell necrosis, not apoptosis. In some neurons, mostly dark and usually with moderate degrees of nuclear degenerative changes, the nuclear pores were decreased in number and obscure 14 and 20 days after DXR administration. DXR enters presumably the nucleus and is partly removed through the nuclear pores. However, the diameters of nuclear pores were similar in DXR-intoxicated and control rats. The changes in nuclear pores of neurons in DXR intoxication, which to our knowledge has not been previously studied, are considered to be part of the degenerative or necrotic changes of DRG neurons.