Sinomenine Ameliorates IL-1β-Induced Intervertebral Disc Degeneration in Rats Through Suppressing Inflammation and Oxidative Stress via Keap1/Nrf2/NF-κB Signaling Pathways

Abstract

Gongbiao Lu,1,2,* Cunxin Zhang,2,* Kang Li,2 Kai Gao,3 Maoqing Fu,2 Chaoliang Lyu,2 Zhengxue Quan1 1Department of Spine Surgery, the First Affiliated Hospital of Chongqing Medical University, Chongqing, 400042, People’s Republic of China; 2Department of Spine Surgery, Jining No.1 People’s Hospital, Jining, 272011, People’s Republic of China; 3Department of Orthopaedics, Jining No.1 People’s Hospital, Jining, 272011, People’s Republic of China*These authors contributed equally to this workCorrespondence: Zhengxue Quan, Department of Spine Surgery, the First Affiliated Hospital of Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing, 400042, People’s Republic of China, Tel [phone], Fax [phone], Email [email protected] Chaoliang Lyu, Department of Spine Surgery, Jining No.1 People’s Hospital, No. 6 Healthy Road, Rencheng District, Jining, 272011, People’s Republic of China, Tel [phone], Fax [phone], Email [email protected]: To investigate the molecular mechanism underlying the inhibitory effect of sinomenine (SN) on interleukin-1β (IL-1β)-induced apoptosis in nucleus pulposus cells (NPCs), and to evaluate the potential role of SN in preventing intervertebral disk degeneration (IDD).Methods: The Rat NPCs were cultured in vitro and identified using Hematoxylin-Eosin (HE) staining, toluidine blue staining, and immunofluorescence analysis. NPCs were pretreated with or without SN, then induced with IL-1β to assess cell viability, ROS levels, apoptotic rates, and wound healing ability. Relevant protein expression was detected using Elisa, qPCR and Western Blot techniques. NPCs were pretreated with SN, either alone or in combination with Nrf2-IN-1 or SC, before being induced to undergo apoptosis by IL-1β. Apoptosis was detected using Hoechst staining, while qPCR and Western Blot techniques assessed protein expression. Rat caudal intervertebral discs were induced with IDD, with or without SN injection, and then co-injected with IL-1β. The levels of IDD were evaluated using HE staining and modified saffron-O-fix green cartilage staining. Relevant protein expression was detected using Elisa, qPCR, and Western Blot techniques.Results: IL-1β significantly reduced NPC activity, induced ROS accumulation and apoptosis, decreased cell healing rate, promoted the expression and secretion of inflammatory factors, and inhibited extracellular matrix synthesis. However, pretreatment with SN effectively reversed these effects. Inhibition of the Keap1/Nrf2 signaling pathway or activation of the NF-κB signaling pathway significantly attenuated the cytoprotective effects of SN and increased apoptosis. Acupuncture combined with IL-1β injection markedly induced intervertebral disc degeneration in rat caudal spine, upregulated inflammatory factors expression and secretion, and downregulated extracellular matrix synthesis. SN intervention notably enhanced antioxidant enzyme expression and reversed these outcomes.Conclusion: SN can prevent IL-1β-induced apoptosis of NPCs and ameliorate IDD by activating the Keap1/Nrf2 pathway and inhibiting the NF-κB signaling pathway.Keywords: sinomenine, intervertebral disc degeneration, nucleus pulposus cells, apoptosis, Nrf2, NF-κB

Keywords

• sinomenine
• intervertebral disc degeneration
• nucleus pulposus cells
• apoptosis
• nrf2
• nf-κb