RETRACTED: TRAF2 gene silencing induces proliferation and represses apoptosis of nucleus pulposus cells in rats with intervertebral disc degeneration (Retracted article. See vol. 319, 2023)

Objective: We aim to research the role of TRAF2 silencing in regulating proliferation and apoptosis of nucleus pulposus cells (NIPCs) in rats with intervertebral disc degeneration (IDD) through mediating NF-xB signaling pathway. Methods: Degenerative disc nucleus pulposus tissues and normal nucleus pulposus tissues were collected to compare the positive expression of TRAF2 protein by immunohistochemistry, and to compare TRAF2, NF-xB (P65) and NF-xB (P50) expression by RT-qPCR and Western blot. A rat model with IDD was replicated using fibrous ring needle method and then treated with TRAF2-siRNA to silence TRAF2. Then, pathological changes and apoptosis in nucleus pulposus tissues were observed. In vitro NIPCs were transfected with TRAF2-siRNA or NF-xB pathway activator (recombinant TNF-a), and then colony formation, proliferation, senescence and apoptosis of NIPCs were determined. Results: Increased TRAF2 and NF-xB were found in nucleus pulposus tissues from IDD patients and rats. Silencing TRAF2 inactivated NF-xB signaling pathway and attenuated pathological damage and apoptosis in nucleus pulposus tissues of rats with IDD. In in-vitro NIPCs, knockdown of TRAF2 resulted in promoted proliferation and colony formation ability while suppressed senescence and apoptosi. The NF-xB pathway activator (recombinant TNF-a) reversed the phenotypic changes of NIPCs resulted from TRAF2 silence. Conclusion: Our study demonstrates that TRAF2 is highly expressed in IDD, and silencing of TRAF2 promotes NIPC proliferation and restrains the apoptosis in IDD.