Upregulation Of CXCL9 By LncRNA-NONRATT021203.2 In Dorsal Root Ganglion Contributes To Bone Cancer Induced Pain In Rats

Objective:Bone cancer induced pain(BCIP)is a chronic pain that progresses over time.The proportion of BCIP is increasing as the survival period of breast cancer continues to increase.However,the mechanisms are largely unknown and clinical treatment remains challenging.According to the recent studies,CXCL9 makes an important contribution to malignancies,inflammation and nociception in human.The previous microarray results suggested that the upstream of CXCL9 may be long non-coding RNA(lncRNA).In various biological processes like cell cycle and signaling pathway,lncRNAs are very important.LncRNA-NONRATT021203.2 can target CXCL9 according to the results of gene chip results.Therefore,the the aim of present study is to investigate whether lncRNA-NONRATT021203.2 participates in the development of BCIP by regulation the expression of CXCL9.Methods:1.Walker 256 cells were used to establish BCIP models.Injecting the cells into tibia canal of the SD female rats.The 10-?L micro syringe with a 23-gauge needle was used.2.To test the paw withdrawal threshold(PWT)of static mechanical stimulation for BCIP rats.Von Frey filaments were used.Thermal pain meter was used to measure the radiant heat paw withdrawal latency(PWL)of BCIP rats.3.CXCL9-siRNA was intrathecally injected to verify role of CXCL9 in BCIP.4.RT-PCR analysis was performed to detect the CXCL9 and related IncRNAs expression level.5.ELISA was performed to detect the protein expression of CXCL9.6.Immunofluorescence was employed for detecting the distribution of CXCL9 in dorsal root ganglions(DRGs).FISH was done for the co-localization of lncRNA-NONRATT021203.2 and CXCL9.Results:1.BCIP rats showed obvious somatic pain.The mRNA and protein levels of CXCL9 were significantly increased in the L2-L5 DRGs.2.Intrathecal injection of CXCL9-siRNA can significantly alleviate pain of BCIP rats by.3.CXCL9 was co-localized with NeruN positive DRG neurons but not with GS positive cells.4.LncRNA-NONRATT021203.2 expression was significantly increased in BCIP rats.5.Intrathecal injection of lncRNA-NONRATT021203.2 siRNA significantly attenuated somatic pain of BCIP rats.6.CXCL9 and lncRNA-NONRATT021203.2 were co-expressed on neurons in the DRGs.After intrathecal injection of lncRNA-NONRATT021203.2 siRNA into BCIP rats,CXCL9 mRNA and protein levels were significantly decreased.Conclusion:LncRNA-NONRATT021203.2 participates in chronic somatic pain in BCIP rats by up-regulating the expression of CXCL9,which provides basis and new targets for the treatment of bone metastasis caused by tumors.