Abstract: Objective To investigate the effects of scutellarin (SCU) on apoptosis of nucleus pulposus cells and the Janus kinas 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway in intervertebral disc degeneration (IVDD) model rats. Methods IVDD rats were randomly divided into IVDD group, SCU low and high dose groups (SCU-L, SCU-H groups), SCU high dose+JAK2 activator bispecific protein phosphatase 19 (DUSP19) group (SCU-H+DUSP19 group)and control group. Enzyme-linked immunosorbent assay (ELISA) method was applied to detect inflammatory factors and oxidative stress level in intervertebral disc tissues. Eosin staining (HE) staining microscopy was used to observe pathological damage of intervertebral disc tissue. Transferase mediated dUTP notch end labeling (TUNEL) staining microscopy was applied to detect apoptosis of nucleus pulposus cells in intervertebral disc tissue. Western blot was applied to detect the expression of JAK2/STAT3 signaling pathway related proteins. Results Animals in the IVDD group were suffered from partial rupture of the fibrous ring in the intervertebral disc tissue, abnormal shrinkage of the nucleus pulposus structure with reduction of nucleus pulposus cells and blurred boundary with the fibrous ring. The level of TNF-α, IL-1β, ROS and apoptosis rate of nucleus pulposus cells, the expression of Bax, cleaved caspase-3, p-JAK2/JAK2, p-STAT3/STAT3 were all elevated and the expression of SOD, type Ⅱ collagen, and polysaccharides decreased (P＜0.05).The morphology, cell structure, density of fibrous ring and nucleus pulposus in the intervertebral disc tissue of the SCU-L and SCU-H groups were improved as compared to IVDD group. The degeneration was alleviated to varying degrees. The level of TNF-α, IL-1β, ROS, apoptosis rate of nucleus pulposus cells and the expression of Bax, cleaved caspase-3, p-JAK2/JAK2, p-STAT3/STAT3 were all reduced and the expression of SOD, type Ⅱ collagen, and polysaccharides significantly increased (P＜0.05). DUSP19 partially reverses the effect of SCU on apoptosis of IVDD rats. Conclusions SCU may alleviate apoptosis of nucleus pulposus cells in IVDD rats.

Key words: scutellarin, intervertebral disc degeneration, nucleus pulposus cells, apoptosis