RETRACTED: GZMB gene silencing confers protection against synovial tissue hyperplasia and articular cartilage tissue injury in rheumatoid arthritis through the MAPK signaling pathway (Publication with Expression of Concern. See vol. 155, 2022) (Publication with Expression of Concern. See vol. 155, 2022) (Retracted article. See vol. 162, 2023)

Introduction: Rheumatoid arthritis (RA) represents the most commonly occurring inflammatory type of arthritis and is a major cause of disability. Reports have placed emphasis on the potential of, granzyme B (GZMB) as a potentially valuable prognostic marker in early RA, the mechanism of which still remains largely unclear. Thus, the aim of the current study was to investigate the effects GZMB gene silencing influences synovial tissue hyperplasia and articular cartilage tissue injury of RA through the regulation of the MAPK signaling pathway. Methods: Following the successful establishment of the collagen-induced animal model of RA in rats, a five-grade scoring method was applied to evaluate the swelling degree measurement of the rats for model identification. The various rat responses to GZMB shRNA and U-46619 (activator of the MAPK signaling pathway) were subsequently detected. The general status of rats was observed and recorded, with their weight and ankle diameter kept accurate record of. ELISA was employed to detect the levels of inflammatory cytokines, while RT-qPCR and Western blotting techniques were applied to determine the expressions of GZMB and pathway-related genes and proteins. Results: GZMB gene silencing was observed to aid in the maintenance of rat weight increases, while acting to reduce the degree of ankle swelling, while hypertrophy of the synovial tissue and the injury of the articular cartilage tissue were not obvious. GZMB gene silencing was shown to decrease inflammatory cytokine levels, as well as decreased bcl-2, Cyclin D1, VEGF and bFGF while increasing caspase 3. Notably, GZMB gene silencing suppressed the activation of the MAPK signaling pathway by reducing the phosphorylation extent of ERK and MEK. Conclusion: Taken together, the key findings of the present study ultimately suggest that GZMB gene silencing acts to inhibit MAPK signaling pathway through regulating the expressions of inflammatory factors, factors correlated with apoptosis (bcl-2 and caspase), as well as factors associated with angiogenesis (VEGF and bFGF), thus relieving synovial tissue hyperplasia and articular cartilage tissue injury brought about by RA. The GZMB gene could well be a new therapeutic target for RA treatment.