Research On The Regulative Functions Of ERK5Signaling Pathway On The Process Of Nucleus Pulposus Cells Degeneration Induced By TNF-α

Objective: To investigate the regulation function of ERK5signaling pathway on theprocess of nucleus pulposus cells degeneration induced by TNF-α.Methods:1.Observe the expression of ERK5in human nucleus pulposus cells by means ofimmunohistochemistry staining. The expression of ERK5in human normal anddegenerative nucleus pulposus tissues were detected by Western blot;2.Detect thedifferent expressions of ERK5and p-ERK5in the process of nucleus pulposusdegeneration induced by TNF-α.3. Nucleus pulposus cells that siRNA-mediatedknockdown of ERK5was stimulated by TNF-α and then the transcription of ERK5,collagen II, AGC and SOX9was detected by RT-PCR.Results:1. The expression of ERK5, located in cytoplasm, was observed in humandegenerative nucleus pulposus cells by means of immunohistochemistrystaining.2.Western blot revealed that no significant difference of the expression of ERK5between normal nucleus pulposus cells and degenerative groups(n=11,P<0.05).But theexpression of p-ERK5in degenerative groups were lower than the normalgroups(n=5,P<0.05).3.Fifteen minutes after TNF-α stimulating, the expression of p-ERK5began to decrease and lasted to sixty minutes.4.There were significant decreases in thegene transcriptions of ERK5, collagen II, AGC and SOX9in human degenerative nucleuspulposus cells that mRNA-mediated knockdown of ERK5with the RT-PCR compared tothe normal groups (n=5,P<0.05) and in greater decreases who stimulated by TNF-αcompared to the no TNF-α stimulated groups(n=5,P<0.05).Conclusion:1.The expression of ERK5, located in cytoplasm, was observed in humandegenerative nucleus pulposus cells.2.The expression of p-ERK5in degenerative nucleuspulposus was lower than the normal one. No significant difference of the expression ofERK5was found between the degenerative and the normal nucleus pulposus tissues.3.TheERK5signal pathway participated in the process of nucleus pulposus cells degenerationinduced by TNF-α. TNF-α may inhibit the activation of ERK5.4.mRNA-mediatedknockdown of ERK5decreased the transcription of ERK5, collagen II, AGC and SOX9.