Sinapine thiocyanate alleviates intervertebral disc degeneration by not regulating JAK1/STAT3/NLRP3 signal pathway

Background. Intervertebral disc degeneration (IDD) is a major cause of low back pain. Sinapine thiocyanate (ST) has been reported to have a wide range of biological activities. However, the treatment of IDD with ST has not been studied. Objectives. To explore the role and mechanism of ST treatment in IDD. Materials and methods. Nucleus pulposus cells (NPCs) were induced using lipopolysaccharide (LPS), which was used as an in vitro model of IDD. Cell activity, oxidative stress -related indicators and protein expression were detected using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, enzyme -linked immunosorbent assay (ELISA) and western blot. Pyroptosis was evaluated with propidium iodide (PI)/Hoechst double staining and immunofluorescence for NOD -like receptor protein 3 (NLRP3), and pyroptosis-related proteins and inflammatory factors were measured with western blot and ELISA. The pathological changes of IDD were assessed with hematoxylin & eosin (H&E) and safranin-O staining. Results. Our results showed that ST alleviated LPS-induced degeneration of NPCs, as evidenced by reducing reactive oxygen species (ROS), malondialdehyde (MDA), matrix metalloproteinase-13 (MMP-13), a disintegrin and metalloproteinase with thrombospondin motifs -5 (ADAMTS-5), and increasing collagen II and aggrecan expression. Moreover, ST repressed LPS-induced pyroptosis by inhibiting NLRP3, caspase-1 p20, interleukin (IL)-1 beta and IL -18. Further studies showed that ST did not restrain the activation of the JAK1/STAT3 signaling pathway induced by colivelin, or of the enhanced pyroptosis induced by polyphyllin VI. Sinapine thiocyanate alleviated IDD in vivo and suppressed NLRP3-mediated pyroptosis and the JAK1/STAT3 signaling pathway. Conclusions. Sinapine thiocyanate could alleviate IDD, although this did not include a reduction in NLRP3mediated pyroptosis and inactivation of the JAK1/STAT3 signaling pathway, thus potentially being a candidate drug for IDD treatment.