Abstract: BACKGROUND: The development of medications that can stop or even reverse the degeneration of articular cartilage has long been a significant scientific concern. Researchers have recently become interested in cell senescence and focused on regulatory techniques.
OBJECTIVE: To explore the regulatory mechanism of remimazolam on chondrocyte senescence in mice, and assess its therapeutic efficacy and mechanism of action in osteoarthritis.
METHODS: (1) In vitro cell experiment: After primary chondrocytes were isolated and cultivated, chondrocyte models of osteoarthritis were induced in vitro using 10 ng/mL interleukin-1β. The optimal intervention concentration of remimazolam on mouse chondrocytes was detected using the cell counting kit-8 assay. Three groups were set up in the experiment: normal control, interleukin-1β, and remimazolam groups. Twenty-four hours after intervention, western blot, immunofluorescence staining, and β-galactosidase assays were used to detect the synthesis and catabolism protein indicators, senescence protein indicators, and nuclear factor-κB signaling pathway-related indicators in mouse chondrocytes. (2) In vivo animal experiment: C57/BL6 mice aged 8 weeks were randomized into three groups: the sham group, the medial meniscus instability group, and the remimazolam group. Following 4 weeks of remimazolam treatment, gait analysis in mice was performed. Pathological changes in the articular cartilage were observed using safranine O-fast green staining. Immunofluorescence staining was used to detect the expression levels of type II collagen and matrix metalloproteinase 13.
RESULTS AND CONCLUSION: (1) In vitro cell experiment: Compared with the interleukin-1β group, interleukin-1β-induced chondrocytes treated with 60 μmol/L remimazolam exhibited a significant decrease in the expression levels of the senescence markers P16 and P21, an increase in the expression of anabolic markers type II collagen and aggrecan, a decrease in the expression of catabolic markers matrix metalloproteinase 3 and matrix metalloproteinase 13, and inhibition of the nuclear-κB signaling pathway. (2) In vivo animal experiment: After 4 weeks of treatment with remimazolam, the mice in the remimazolam group showed recovered lower limb function, improved histopathological scores, increased expression of type II collagen, decreased expression of matrix metalloproteinase 13 compared with those in the medial meniscus instability group. To conclude, by blocking the nuclear factor-κB signaling pathway, remimazolam alleviates chondrocyte senescence and enhances cartilage structure, offering a novel approach to treating osteoarthritis.

Key words: osteoarthritis, remimazolam, chondrocytes, cellular senescence, nuclear factor-κB signaling pathway, type II collagen, matrix metalloproteinase