Periostin Alleviates IL-1β-Induced Nucleus Pulposus Cell Inflammation And Apoptosis Through The NF-κB Signaling Pathway

Objective: To detect the expression of Periostin(POSTN)in normal and degenerated disc nucleus pulposus tissue(NP)and to further investigate the relationship between POSTN and inflammation and apoptosis in rat nucleus pulposus cells(NPCs).Methods: Based on the Pffirmann classification of Intervertebral Disc Degeneration(IVDD),NP tissue samples with different degenerative grades were collected.The expression of POSTN,p-P65,i NOS and C-caspase3 in the tissues of different degeneration grades was detected by Western Blot and immunohistochemistry.Subsequently,we established a rat IVDD model using the needle-stick modeling method,and detected the expression of POSTN,p-P65,i NOS and C-caspase3 in normal and degenerated rat NP by Western Blot and immunohistochemistry.In addition,we established IL-1β-induced NP cell degeneration model using lentivirus-carried small interfering RNA(si-RNA)to suppress POSTN expression and CU-T12-9 to activate NF-κB signaling pathway.The expression of proteins related to the level of inflammatory response and apoptosis in NPCs as well as changes in the expression of related protein indicators in the NF-κB signaling pathway were detected by Western Blot and immunofluorescence.Results: Immunohistochemical assays revealed that the rate of positive cells for POSTN was higher in degenerated NP tissues compared to normal NP tissues in humans and rats.And Western Blot also confirmed that the expression of POSTN protein was significantly higher in the degenerated NP tissues.In an in vitro IL-1β-induced degeneration model of NPCs,the expression of POSTN was found to be significantly increased in degenerating rat NPCs by immunofluorescence detection and Western Blot.When the expression of POSTN in cells was inhibited by transfection with lentivirus-carried si-POSTN,it was found by Western Blot that the expression of inflammatory factors i NOS,COX-2,IL-6 and pro-apoptosis-related proteins C-caspase3 and BAX,which were originally elevated in NPCs induced by IL-1β,was reduced,while the expression of anti-apoptosis,which was originally reduced The expression of Bcl-2,an anti-apoptotic-related protein,was increased,and the fluorescence intensity of i NOS by immunofluorescence and the rate of apoptosis-positive cells by TUNEL staining were also obtained accordingly.Moreover,the inhibition of POSTN expression also inhibited the nuclear translocation of P65,which acted as an inhibitor of NF-κB signaling pathway activity.And when NPCs were treated with the NF-κB signaling pathway activator CU-T12-9,the protective effect of si-POSTN on IL-1β-induced inflammation and apoptosis in NPCs was reversed.Conclusions: POSTN expression is elevated in IVDD,and POSTN down-regulation alleviates the inflammatory response and apoptotic levels in degenerating NPCs by inhibiting the NF-κB signaling pathway.