| Objective To investigate the effects of TNF-αand IL-6 on apoptosis of human nucleus pulposus cell. Methods The human nucleus pulposus cells were cultured. The cells were divided into 7 groups at random:group treated with TNF-α, group treated with TNF-α+10μmol/L SB203580, group treated with TNF-α+10μmol/L SP600125, group treated with IL-6, group treated with IL-6+10μmol/L SB203580, group treated with IL-6+10μmol/L SP600125 and the control group. Flow cytometric assay was to detect the human nucleus pulposus cell apoptosis. The density of human nucleus pulposus cells of apoptosis was detected by TUNEL method in each group. The expression and cellular localization of P-P38MAPK and P-JNK/SAPK were investigated by immunohistochemistry. The expression of total JNK/SAPK, P38MAPK and their phosphorylations were investigated by Western blotting. Results There was higher density of human nucleus pulposus cells of apoptosis in TNF-αand IL-6 groups than that in the control group and that in groups with inhibition(P<0.01). The phosphorylation expressions of P38MAPK and JNK/SAPK were increased after treatment with TNF-αand IL-6. The expression of phosphorylations of P38MAPK or JNK/SAPK were significantly inhibited with the pretreatment of SB203580 or SP600125 compared with that in the TNF-αgroup and IL-6 group in both immunofluorescence analysis and western blotting. Immunofluorescence analysis also demonstrated that P-P38MAPK and P-JNK/ SAPK were expressed and distributed mainly in cytoplasmic and nuclear in the TNF-αgroup and IL-6 group, however, with no P-P38MAPK and P-JNK/SAPK in the control group and groups with inhibition. Conclusions TNF-a and IL-6 induces the apoptosis of human nucleus pulposus cell via P38MAPK and JNK/SAPK pathway. |
