title: Bortezomib-induced peripheral neurotoxicity: a neurophysiological and pathological study in the rat.
abstract: Bortezomib is a new proteasome inhibitor with a high antitumor activity, but also with a potentially severe peripheral neurotoxicity. To establish a preclinical model and to characterize the changes induced on the peripheral nerves, dorsal root ganglia (DRG) and spinal cord, bortezomib was administered to Wistar rats (0.08, 0.15, 0.20, 0.30 mg/kg/day twice [2q7d] or three times [3q7d] weekly for a total of 4 weeks). At baseline, on days 14, 21 and 28 after the beginning the treatment period and during a 4-week follow-up period sensory nerve conduction velocity (SNCV) was determined in the tail of each animal. Sciatic nerve, DRG and spinal cord specimens were processed for light and electron microscope observations and morphometry. At the maximum tolerated dose bortezomib induced a significant reduction in SNCV, with a complete recovery at the end of the follow-up period. Sciatic nerve examination and morphometric determinations demonstrated mild to moderate pathological changes, involving predominantly the Schwann cells and myelin, although axonal degeneration was also observed. Bortezomib-induced changes were also observed in DRG and they were represented by satellite cell intracytoplasmatic vacuolization due to mitochondrial and endoplasmic reticulum damage, closely resembling the changes observed in sciatic nerve Schwann cells. Only rarely did the cytoplasm of DRG neurons has a dark appearance and clear vacuoles occurring in the cytoplasm. Spinal cord was morphologically normal. This model is relevant to the neuropathy induced by bortezomib in the treatment of human malignancies and it could be useful in increasing our knowledge regarding the mechanisms underlying bortezomib neurotoxicity.
authors.affiliation: Department of Neurosciences and Biomedical Technologies, University of Milan Bicocca, Monza, Italy. guido.cavaletti@unimib.it
authors.forename: Guido
authors.initials: G
authors.lastname: Cavaletti
authors.forename: Alessandra
authors.initials: A
authors.lastname: Gilardini
authors.forename: Annalisa
authors.initials: A
authors.lastname: Canta
authors.forename: Laura
authors.initials: L
authors.lastname: Rigamonti
authors.forename: Virginia
authors.initials: V
authors.lastname: Rodriguez-Menendez
authors.forename: Cecilia
authors.initials: C
authors.lastname: Ceresa
authors.forename: Paola
authors.initials: P
authors.lastname: Marmiroli
authors.forename: Mario
authors.initials: M
authors.lastname: Bossi
authors.forename: Norberto
authors.initials: N
authors.lastname: Oggioni
authors.forename: Maurizio
authors.initials: M
authors.lastname: D'Incalci
authors.forename: Roland
authors.initials: R
authors.lastname: De Coster
mesh_terms: D000818:Animals; D001897:Boronic Acids / Q000633:toxicity; D000069286:Bortezomib; D005260:Female; D005727:Ganglia, Spinal / Q000473:pathology; D008854:Microscopy, Electron; D009431:Neural Conduction; D009475:Neurons, Afferent; D009498:Neurotoxins / Q000633:toxicity; D010523:Peripheral Nervous System Diseases / Q000139:chemically induced* / Q000473:pathology / Q000503:physiopathology; D011719:Pyrazines / Q000633:toxicity; D051381:Rats; D017208:Rats, Wistar; D012584:Sciatic Nerve / Q000473:pathology; D013116:Spinal Cord / Q000473:pathology; D013623:Tail / Q000294:innervation
chemical_list: D001897:Boronic Acids; D009498:Neurotoxins; D011719:Pyrazines; D000069286:Bortezomib