Background: Although Chemotherapy-induced peripheral neuropathy (CIPN) is a significant side effect associated with many chemotherapeutic agents, there are no analgesics that effectively treat this disorder. Microarray gene analyses of nervous system tissues hold great promise for the identification and development of novel targets for persistent pain modulation. Thus, the aim of the present study was to determine in gene expression changes in a rat model of CIPN. 
Methods: A rat model of cisplatin-induced peripheral neuropathic pain was used in the present study. Mechanical allodynia was measured using von Frey filaments, and global gene expression in the lumbar spinal cord (SC) and dorsal root ganglion (DRG) was analyzed at 5 and 14 days following cisplatin administration. Finally, the validity of the array results was evaluated using real-time reverse-transcription polymerase chain reaction (qRT-PCR).
Results: The microarray analyses revealed significant differences in the mRNA expression profiles of cisplatin-injected and vehicle-injected rats. On day 5 after cisplatin injection, 186 altered mRNAs (128 up-regulated and 58 down-regulated) were identified in the SC, and 197 altered mRNAs (145 up-regulated and 52 down-regulated) were identified in the DRG. On day 14 after cisplatin injection, 220 altered mRNAs (130 up-regulated and 90 down-regulated) were identified in the SC, and 198 altered mRNAs (133 up-regulated and 65 down-regulated) were identified in the DRG. The expression patterns of several mRNAs were further confirmed by qRT-PCR. The gene ontology results showed that the most significantly enriched biological processes associated with the up-regulated genes included immune responses and chemical stimulus detection in the SC and cellular homeostasis and muscle system processes in the DRG. 
Conclusions: Changes in mRNA expression patterns were identified in rat SC and DRG under conditions of CIPN. These altered mRNAs may represent novel therapeutic targets for the treatment of neuropathic pain. Further studies are needed to elucidate the roles of individual genes in CIPN.
Acknowledgements: This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Science, ICT and Future Planning (NRF-2015R1A2A2A01004407). All authors declare that no competing financial interests exist.

Gene expression profile of spinal cord and dorsal root ganglion in rat model of cisplatin-induced peripheral neuropathic pain