Preliminary research on the mechanisms of bone cancer pain is developed in recent years, the mechanisms of CIBP remain unclear. Previous studies have indicated Ganetespib cell in vivo in vitro the critical roles of MAPK, including the roles of extracellular signal regulated kinases and p38 in chronic pain, however, the particular roles of JNK activation of bone cancer pain in the spinal cord remain unclear. In this study, we found that JNK was activated at different time points in the spinal-cord after intra tibial inoculation with carcinoma cells, improved pJNK degrees were co expressed with NeuN and GFAP but not CD11b, a single intrathecal injection of JNK inhibitor SP600125 by lumbar puncture attenuated CIBP on day 12. These proposed that JNK activation in the back participated in the development of CIBP. Sustained activation of pJNK1/2 inside the spinal cord after intra tibial inoculation with carcinoma cells pJNK1 and pJNK2 protein levels were detected to the ipsilateral side of L4 L5 spinal cord. We analyzed the appearance of pJNK1/2 in either CIBP or a PBS control group at various Extispicy time points after surgery. . pJNK1/2 and GAPDH were found in exactly the same membrane. The levels of pJNK1/2 were not changed in comparison with the nave group on day 5, day 12 or day 16 following the injection of PBS as a sham control. Compared to nave rats, the pJNK1/2 protein levels were increased on the ipsilateral side of the spinal cord on day 16 and day 12 after intra tibial inoculation with carcinoma cells. The amount of pJNK positive cells was also increased by single stained immunofluorescence on day 16 and day 12 after inoculation with carcinoma cells. We then identified the cellular localization of pJNK1/2 in nave and model animals. Double immunofluorescence chk2 inhibitor showed that a small amount of pJNK1/2 IR cells were double labeled with NeuN, CD11b and GFAP, indicating that pJNK1/2 was expressed in neurons and microglia, astrocytes in nave mice. . A significant increase in the number of pJNK1/2 IR neurons and astrocytes was found on day 12 and day 16 in ipsilateral back after intra tibial inoculation with carcinoma cells as compared to the nave condition, but the number of pJNK1/2 IR microglia wasn’t changed at any time level after intra tibial inoculation with carcinoma cells. Analgesic effects of intrathecal JNK chemical SP600125 The CIBP subjects exhibited significant decreases in physical thresholds on day 5, day 12 and day 16 after intra Figure 1 Time course of pJNK up-regulation on the ipsilateral side of L4 L5 back after intra tibial inoculation with carcinoma cells. Representative Western blots of GAPDH and pJNK1/2 from one membrane. Density of pJNK1/2 levels to the ipsilateral side of L4 L5 spinal-cord. pJNK1/2 levels were normalized against GAPDH levels and expressed as fold increase, in contrast to nave..