Resveratrol protects human nucleus pulposus cells from degeneration by blocking IL-6/JAK/STAT3 pathway

Background Nucleus pulposus cells' (NPCs') degeneration is mainly responsible for the intervertebral disc degeneration (IDD), which is closely related to inflammatory response. Among the major proinflammatory factors that are related to NPCs' degeneration, interleukin-6 (IL-6) and its downstream JAK/STAT3 pathway have received recent attention. The goal of our study is to figure out whether or how resveratrol (RSV) can protect NPCs from degeneration by affecting IL6/JAK/STAT3 pathway. Methods Different concentrations of RSV were added to NPCs' mediums. Cell viability was measured by MTT assay and crystal violet staining. Cell cycle and apoptosis were analyzed by flow cytometry. Protein expression level was determined by western blot. mRNA expression level was measured by qPCR. Results Our study showed that RSV improved NPCs' cell viability. It also inhibited cell apoptosis and cell cycle arrest, which were accompanied by the increased expression level of heat shock protein 90 (HSP90) and N-Cadherin. What' more, RSV also improved the NPCs' degeneration which was reflected in the increase of extracellular matrix (collagen II, Aggrecan). Moreover, RSV significantly attenuated the level of IL-6 secretion, which was accompanied by less phosphorylation of the transcription factors Janus kinase 1 (JAK1) and signal transducer and activator of transcription 3 (STAT3). Conclusion RSV exerted its protective effect on HNPCs' degeneration by improving cell survival and function. The possible mechanism may be associated with the suppression of JAK/STAT3 phosphorylation and the decreased IL-6 production, which could be explained by a blockage of the positive feedback control loop between IL-6 and JAK/STAT3 pathway.