Ruoyu Zhao,1 Lei Ma,2 Joan Li,3 Sen Liu,1 Dalong Yang,2 Guobin Liu,1 Sidong Yang4 

1Department of Orthopedic Surgery, the First Hospital of Hebei Medical University, Shijiazhuang, Hebei, People’s Republic of China; 2Department of Spine Surgery, Hebei Medical University Third Hospital, Shijiazhuang, Hebei, People’s Republic of China; 3Medical School, Faculty of Medicine, the University of Queensland, Brisbane, Queensland, Australia; 4Department of Orthopedic Surgery, Hebei Medical University Third Hospital, Shijiazhuang, Hebei, People’s Republic of China

Correspondence: Sidong Yang, Department of Orthopedic Surgery, Hebei Medical University Third Hospital, Shijiazhuang, People’s Republic of China, Email sidongyang@hebmu.edu.cn Guobin Liu, Department of Orthopedic Surgery, the First Hospital of Hebei Medical University, Shijiazhuang, People’s Republic of China, Email liuguobin@hebmu.edu.cn

Purpose: This study aimed to investigate the protective effect of adipose tissue-derived exosomes (AT-Exo) on rat nucleus pulposus cells (NPCs).
Methods: Ultracentrifugation was used to extract exosomes from rat adipose tissue. Transmission electron microscopy (TEM), Western blot, and nanoparticle tracking analysis (NTA) were used to characterize the exosomes. Tert-butyl hydrogen peroxide (TBHP) was used to induce apoptosis of rat NPCs. Cell viability was determined by CCK-8 assay. AT-Exo was administered to investigate its effect on rat NPCs using Western blot and immunofluorescence staining.
Results: AT-Exo was successfully extracted and characterized by NTA, TEM, and Western blots. Uptake assay showed that AT-Exo can be taken up by the NPCs. TBHP (60 μM) resulted in decreased cell viability and increased apoptosis of NPCs. Interestingly, AT-Exo protected NPCs against TBHP, indicated by increased cell viability, decreased apoptosis, upregulated Aggrecan and type II collagen deposition, and downregulated matrix metalloproteinase 3/13.
Conclusion: In summary, rat adipose tissue-derived exosomes can increase the levels of Aggrecan, type II collagen, and Bcl2, and decrease the levels of matrix metalloproteinase 3/13, cleaved caspase3, and Bax. Therefore, rat adipose tissue-derived exosomes can maintain metabolic balance of extracellular matrix and protect against apoptosis in rat nucleus pulposus cells.

Keywords: exosome, adipose, intervertebral disc degeneration, nucleus pulposus, extracellular matrix