The Role Of Spinal IL-6-JAK2-STAT3 Signaling Transduction Pathway Regulating Astrocytes Activation During The Maintenance Of Bone Cancer Pain In A Mouse Model

Objective:To investigate the role of spinal interleukin-6-Janus Kinase2-Signal Transducers and Activators of Transcription3 signaling transduction pathway regulating astrocytes activation during the maintenance of bone cancer pain.Methods:The femur marrow cavity of C3H/He NCrl Vr male mice were injected with NCTC 2472 fibrosarcoma cells to make bone cancer pain model and NCTC 2472 fibrosarcoma cells were replaced by the equal volume of ?-MEM in the sham model.The number of spontaneous foot lifting /2 min and paw withdrawal thermal latency(PWTL)were used to assess pain behaviours performance.The lumbar enlargement of spinal cord(L3-L5)was sepreted,and Real-time quantitative RT-PCR and immunofluorescence techonology were used to detect the expression of spinal Glial Fibrillary Acidic Protein(GFAP),interleukin-6(IL-6),Janus Kinase-2(JAK2),Signal Transduction and Transcriptional Activator-3(STAT3)and Transcription Activation Factor(p300/CBP)m RNA and protein respectively.The level of spinal IL-6 and GFAP m RNA expression indirectly reflect astrocytes activation level.To treat mice by intrathecal administration of JAK2 antagonist AG-490,STAT3 antagonist stattic and C646 p300/CBP antagonist,and to observe pain behavior and spinal cord GFAP and IL-6 m RNA expression change at the given time point.Results:(1)NCTC 2472 fibrosarcoma cells inoculation of the femur of the male C3H/He NCrl Vr mice produced progressive spontaneous flinches and thermal hyperalgesia(P<0.05);(2)NCTC 2472 fibrosarcoma cells inoculation of the femur of the male C3H/He NCrl Vr mice induced the expression of GFAP,IL-6,JAK2 and STAT3 m RNA and protein(P<0.05);(3)Intrathecal injection of AG-490,stattic and C646 could improve bone cancer pain behaviors and inhibit the expression of spinal GFAP and IL-6 m RNA(P<0.05).Conclusions: Spinal IL-6-JAK2-STAT3 signaling pathway by regulating spinal GFAP expression levels to affect the activation of astrocytes,which play an important role in the maintenance of bone cancer pain.AG-490,stattic and C646 could improve bone cancer pain behaviors,and inhibiting IL-6-JAK2-STAT3 signal transduction pathway to reduce spinal astrocyte activation may be one of their mechanisms.