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Rheumatoid arthritis (RA) is a chronic and inflammatory synovitis systemic disease. Due to the unknown pathogenesis, this study was to investigate the effect of microRNA (miR)-411 on apoptosis and joint function of synoviocytes in RA mice via RIPK1-mediated NF-κB signaling pathway. The collagen-induced arthritis model mice were induced via collagen type II and Freund's adjuvant. The mice were injected with miR-411 mimics, si-RIPK1 or miR-411 mimics + oe-RIPK1 to figure out their roles in cell apoptosis and inflammation of synovial tissues. Synoviocytes were grouped as in animal experiments. Proliferation and apoptosis of synoviocytes were detected upon treatment with overexpressed miR-411 and silenced RIPK1. The expression of miR-411, RIPK1 and NF-κB in synovial tissues and synoviocytes of RA mice was detected by RT-qPCR and Western blot analysis. Poorly expressed miR-411, and highly expressed NF-κB and RIPK1 existed in synovial tissue and synoviocytes of RA. Additionally, it was found that si-RIPK1 decreased NF-κB expression, and miR-411 mimics decreased both RIPK1 and NF-κB. MiR-411 had a targeted relationship with RIPK1. si-RIPK1 or miR-411 mimics promoted cell apoptosis and strained inflammation in synovial tissues of mice with RA. Overexpressed miR-411 or silencing RIPK1 inhibited the proliferation and promoted apoptosis of synoviocytes of RA mice. Up-regulation of miR-411 or down-regulation of RIPK1 had a certain inhibitory effect on RA. This study suggests that up-regulated miR-411 or down-regulated RIPK1 promoted apoptosis and inhibited proliferation of synoviocytes of RA mice, which may be related to the inhibition of NF-κB activation. [ABSTRACT FROM AUTHOR]

Background: The maintenance of nucleus pulposus (NP) viability in vitro is difficult. The annulus fibrosus (AF) pathway reflects one nutrient transport channel and may have an important effect on NP viability in disc organ cultures. The present study describes a feasible disc pre-treatment involving the AF and investigates its efficacy in improving NP bioactivity in an in vitro disc bioreactor culture.Methods: Rabbit discs that were randomly assigned to the experimental group (EG) were pretreated via the surgical removal and controlled trypsinization of the outer AF. The discs in the control group (CG) did not receive any special treatment. All discs were organ-cultured in a self-developed bioreactor. Solute transport into the central NP was measured using a methylene blue solution. On days 7 and 14, histological properties, cell viability, cell membrane damage, gene expression and matrix composition within the NP in these two groups were compared with each other and with the corresponding parameters of fresh NP samples. Additionally, the structures of the outer AF and the cartilage endplate (CEP) following pre-treatment were also assessed.Results: The outer AF in the EG became disorganized, but no specific changes occurred in the CEP or the inner AF following pre-treatment. The discs in the EG exhibited increased penetration of methylene blue into the central NP. On days 7 and 14, the NP bioactivity in the EG was improved compared with that of the CG in terms of cell viability, cell membrane damage, gene expression profile and matrix synthesis. Moreover, cell viability and matrix synthesis parameters in the EG were more similar to those of fresh samples than they were to the same parameters in the CG on day 14.Conclusions: Using this disc pre-treatment, i.e., the surgical removal and controlled trypsinization of the outer AF, NP bioactivity was better maintained for up to 14 days in an in vitro disc bioreactor culture. [ABSTRACT FROM AUTHOR]