Adipose Tissue-Derived Exosome Maintains Metabolic Balance of Extracellular Matrix in Rat Nucleus Pulposus Cells.

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.